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Micronutrient cofactor research with extensions to applications

Published online by Cambridge University Press:  19 February 2013

Donald B McCormick*
Affiliation:
Department of Biochemistry and Program in Nutrition and Health Sciences, Emory University, Atlanta, GA 30322-3050, USA
*
Correspondance auther:Donald B. McCormick,fax +1 770 938 2215, email [email protected]
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Abstract

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Following identification of essential micronutrients, there has been a continuum of research aimed at revealing their absorption, transport, utilization as cofactors, and excretion and secretion. Among those cases that have received our attention are vitamin B6, riboflavin, biotin, lipoate, ascorbate, and certain metal ions. Circulatory transport and cellular uptake of the water-soluble vitamins exhibit relative specificity and facilitated mechanisms at physiological concentrations. Isolation of enzymes and metabolites from micro–organisms and mammals has provided information on pathways involved in cofactor formation and metabolism. Kinases catalysing phosphorylation of B6 and riboflavin have a preference for Zn2+ in stereospecific chelates with adenosine triphosphate. The synthetase for flavin adenine dinucleotide prefers Mg2+. The flavin mononucleotide-dependent oxidase that converts the 5′–phosphates of pyridoxine and of pyridoxamine to pyridoxal phosphate is a connection between B6 and riboflavin and is a primary control point for conversion of B6 to its coenzyme. Sequencing and cloning of a side–chain oxidase for riboflavin was achieved. Details on binding and function have been delineated for some cofactor systems, especially in several flavoproteins. There is both photochemical oxidation and oxidative catabolism of B6 and riboflavin. Both biotin and lipoate undergo oxidation of their acid side chains with redox cleavage of the rings. Applications from our findings include the development of affinity absorbents, enhanced drug delivery, delineation of residues in biopolymer modification, pathogen photoinactivation in blood components, and input into human dietary recommendations. Ongoing and future research in the cofactor arena can be expected to add to this panoply. At the molecular level, the way in which the same cofactor can participate in diverse catalytic reactions resides in interactions with surrounding enzyme structures that must be determined case by case. At the level of human intake, more knowledge is desirable for making micronutrient recommendations based on biochemical indicators, especially for the span between infancy and adulthood.

Type
Research Article
Copyright
Copyright © CABI Publishing 2002

References

Addison, R & McCormick, DB (1978) Biogenesis of flavoprotein and cytochrome components in hepatic mitochondria from riboflavin–deficient rats. Biochemical and Biophysical Research Communications 81, 133138.Google Scholar
Arsenis, C & McCormick, DB (1964a) Purification of liver flavokinase by column chromatography on flavin–cellulose compounds. Journal of Biological Chemistry 239, 30933097.Google Scholar
Arsenis, C & McCormick, DB (1964 b) Coenzyme specificity of NADPH–cytochrome c reductase for flavin phosphates. Biochimica et Biophysica Acta 92, 440445.Google ScholarPubMed
Arsenis, C & McCormick, DB (1966) Purification of flavin mononucleotide dependent enzymes by column chromatography on flavin phosphate cellulose compounds. Journal of Biological Chemistry 241, 330334.CrossRefGoogle ScholarPubMed
Aw, T-Y, Jones, DP & McCormick, DB (1983) Uptake of riboflavin by isolated rat liver cells. Journal of Nutrition 113, 12491254.CrossRefGoogle ScholarPubMed
Bacher, A, Eberhardt, S, Fisher, M, Kis, K & Richter, G (2000) Biosynthesis of vitamin B2 (riboflavin). Annual Review of Nutrition 20, 153167.Google Scholar
Bender, DA (1992) Nutritional Biochemistry of the Vitamins, pp : Cambridge: Cambridge University Press.Google Scholar
Bowers-Komro, DM, Hagen, TM & McCormick, DB (1986) Modified purification of pyridoxamine (pyridoxine) 5'–phosphate oxidase from rabbit liver 5'–phosphopyridoxyl affinity chromatography. Methods in Enzymology 122, 116120.CrossRefGoogle Scholar
Bowers-Komro, DM & McCormick, DB (1984 a) Mechanism and function of FMN in pyridoxine (pyridoxamine) 5'–phosphate oxidase. In Flavins and Flavoproteins, pp. 581584 [Bray, RC, Engel, PC and Mayhew, SG editors]. New York: Walter de Gruyter.Google Scholar
Bowers-Komro, DM & McCormick, DB (1984 b) Steric restrictions in the active-site region of Liver pyridoxamine (pyridoxine) 5'–phosphate oxidase. In Chemical and Biological Aspects of Vitamin B6 Catalysis. part A: pp. 387396 [Evangelopoulos, AE editor]. New York: Alan R. Liss.Google Scholar
Bowers-Komro, DM & McCormick, DB (1985 a) Pyridoxamine 5'–phosphate oxidase exhibits no specificity in prochiral hydrogen abstraction from substrate. Journal of Biological Chemistry 260, 95809582.Google Scholar
Bowers-Komro, DM & McCormick, DB (1985 b) Biotin uptake by isolated rat liver hepatocytes. Annals of the New York Academy of Sciences 447, 350358.Google Scholar
Bowers-Komro, DM & McCormick, DB (1987) Single– and double–headed analogs of pyridoxamine 5'–phosphate as probes for pyridoxamine 5'–phosphate utilizing enzymes. Bioorganic Chemistry 15, 224236.CrossRefGoogle Scholar
Bowers-Komro, DM, Yamada, Y & McCormick, DB (1989) Substrate specificity and variables affecting efficiency of mammalian flavin adenine dinucleotide synthetase. Biochemistry 28, 84398446.Google Scholar
Bowman, BB & McCormick, DB (1987) Pyridoxine uptake by proximal tubular epithelial cells isolated from rat kidney. In Biochemistry of Vitamin B6., pp. 403406 [Korpela, T and Christen, P editors]. Basel: Birkhauser.Google Scholar
Bowman, BB & McCormick, DB (1989) Pyridoxine uptake by rat renal proximal tubular cells. Journal of Nutrition 119, 745749.Google Scholar
Bowman, BB, McCormick, DB & Rosenberg, IH (1989) Epithelial transport of water-soluble vitamins. Annual Review of Nutrition 9, 187199.CrossRefGoogle ScholarPubMed
Brady, RN, Li, LF, McCormick, DB & Wright, LD (1965) Bacterial and enzymatic degradation of biotin. Biochemical and Biophysical Research Communications 19, 777778.Google Scholar
Brady, RN, Ruis, H, McCormick, DB & Wright, LD (1966) Bacterial degradation of biotin, catabolism of 14C–biotin and its sulfoxides. Journal of Biological Chemistry 241, 47174721.Google Scholar
Chang, HH, Rozo, ML & McCormick, DB (1975) Lipoate metabolism in Pseudomonas putida LP. Archives of Biochemistry and Biophyics 169, 244251.CrossRefGoogle ScholarPubMed
Chassy, BM, Arsenis, C & McCormick, DB (1965) The effect of the side chain of flavins on reactivity with flavokinase. Journal of Biological Chemistry 240, 13381340.CrossRefGoogle ScholarPubMed
Chassy, BM & McCormick, DB (1965 a) Structural requirements of the moiety of flavin–adenine dinucleotide for intramolecular complex formation. Biochemistry 4, 26122615.CrossRefGoogle ScholarPubMed
Chassy, BM & McCormick, DB (1965 b) Coenzyme specificity of D–amino acid oxidase for the flavin moiety of FAD. Biochimica et Biophysica Acta 110, 9196.CrossRefGoogle ScholarPubMed
Chastain, JL & McCormick, DB (1987 a) Clarification and quantification of primary (tissue) and secondary (microbial) catabolites of riboflavin which are excreted in mammalian (rat) urine. Journal of Nutrition 117, 468475.CrossRefGoogle Scholar
Chastain, JL & McCormick, DB (1987 b) Flavin catabolites: Identification and quantitation in human urine. American Journal of Clinical Nutrition 46, 830834.CrossRefGoogle ScholarPubMed
Chastain, JL & McCormick, DB (1988) Characterization of a new flavin metabolite from human urine. Biochimica et Biophysica Acta 967, 131134.CrossRefGoogle ScholarPubMed
Chen, H & McCormick, DB (1997 a) Riboflavin 5'–hydroxymethyl oxidation: Molecular cloning, expression and glycoprotein nature of the 5'–aldehyde forming enzyme from Schizophyllum commune. Journal of Biological Chemistry 272, 2007720081.Google Scholar
Chen, H & McCormick, DB (1997 b) Fungal riboflavin 5'–hydroxymethyl dehydrogenase catalyzes formation of both the aldehyde (riboflavinal) and the acid (riboflavinoic acid). Biochimica et Biophysica Acta 1342, 116118.Google Scholar
Chia, CP, Addison, R & McCormick, DB (1978) Absorption, metabolism, and excretion of 8α–(amino acid)riboflavins in the rat. Journal of Nutrition 108, 373381.Google Scholar
Choi, JD, Bowers-Komro, DM, Davis, MD, Edmondson, DE & McCormick, DB (1983) Kinetic properties of pyridoxine (pyridoxamine) 5'–phosphate oxidase from rabbit liver. Journal of Biological Chemistry 258, 840845.CrossRefGoogle ScholarPubMed
Choi, JD, Davis, MD, Bowers-Komro, DM, Edmondson, DE & McCormick, DB (1982) Steady–state kinetic properties of pyridoxamine (pyridoxine) 5'–phosphate oxidase from rabbit liver. In Flavins and Flavoproteins. pp. 208212 [Massey, V and Williams, CH Jr editors]. New York: Elsevier Biomedical.Google Scholar
Choi, JD & McCormick, DB (1980) The interaction of flavins with egg white riboflavin–binding protein. Archives of Biochemistry and Biophysics 204, 4151.CrossRefGoogle ScholarPubMed
Choi, JD & McCormick, DB (1981) Roles of arginyl residues in pyridoxamine (pyridoxine) 5'–phosphate oxidase from rabbit liver. Biochemistry 20, 57225728.Google Scholar
Combs, GF Jr (1998) In The Vitamins. Functional Aspects in Nutrition and Health. pp : 2nd ed. San Diego: Academic Press.Google Scholar
DePecol, ME & McCormick, DB (1980) Syntheses, properties, and use of fluorescent (N–5'–phospho7–4'–pyridoxyl)amines in assay of pyridoxamine (pyridoxine) 5'–phosphate oxidase. Analytical Biochemistry 101, 435441.Google Scholar
Falk, MC, Johnson, PG & McCormick, DB (1976) Synthetic flavinyl-peptides related to the active site of mitochondrial monoamine oxidase. I. Chemical and spectral properties. Biochemistry 15, 639645.CrossRefGoogle Scholar
Falk, MC & McCormick, DB (1976) Synthetic flavinyl–peptides related to the active site of mitochondrial monoamine oxidase. II. Fluorescence properties. Biochemistry 15, 646653.Google Scholar
Flint, DH & Allen, RM (1997) Purification and characterization of biotin synthetases. Methods in Enzymology 279, 349356.CrossRefGoogle Scholar
Foley, BA, MacKenzie, RE & McCormick, DB (1967) Transport and storage of 14C-riboflavin in the retina and liver of rats. Proceedings of the Society for Experimental Biology and Medicine 126, 715718.Google Scholar
Food and Nutrition Board and Institute of Medicine. Dietary Reference Intakes (1998) Washington, DC: National Academy Press.Google Scholar
Fory, W, MacKenzie, RE & McCormick, DB (1968) Flavinyl peptides. I. Syntheses of flavinyl–aromatic amino acids. Journal of Heterocyclic Chemistry 5, 625630.CrossRefGoogle Scholar
Fory, W, MacKenzie, RE, Wu, FYH & McCormick, DB (1970 a) Flavinyl peptides. II. Intra-molecular interactions in flavinyl–aromatic amino peptides. Biochemistry 8, 18391844.Google Scholar
Fory, W, MacKenzie, RE, Wu, FYH & McCormick, DB (1970 b) Flavinyl peptides. III. Studies of intramolecular interactions in flavinyl aromatic amino acids by proton magnetic resonance. Biochemistry 9, 515525.CrossRefGoogle Scholar
Froehlich, JA, Merrill AH, JR, Clagett, CO & McCormick, DB (1980) Affinity chromatographic purification and comparison of riboflavin–binding proteins from laying hen liver and blood and from egg yolk. Comparative Biochemistry and Physiology 66, 397401.Google Scholar
Furr, HC, Chang, HH & McCormick, DB (1978 a) Lipoate metabolism in Pseudomonas putida LP: Thiolsulfinates of lipoate and bisnorlipoate. Archives of Biochemistry and Biophysics 185, 576583.CrossRefGoogle ScholarPubMed
Furr, HC & McCormick, DB (1978 b) Bacterial catabolism of lipoic acid. Isolation and identification of a methyl ketone. International Journal of Vitamin and Nutrition Research 48, 6871.Google ScholarPubMed
Getoff, N, Solar, S & McCormick, DB (1978 c) Photoejection of electrons from flavins in polar media. Science 201, 616618.Google Scholar
Gomes, B & McCormick, DB (1983) Purification and general characterization of FAD synthetase from rat liver. Proceedings of the Society for Experimental Biology and Medicine 172, 250254.Google Scholar
Griesser, R, Hayes, MG, McCormick, DB, Prijs, B & Sigel, H (1971) Mn2+, Cu2+, and Zn2+ 1:1 complexes with biochemically significant thioether carboxylic acids and the sulfoxide and sulfone derivatives. Archives of Biochemistry and Biophysics 144, 628635.Google Scholar
Griesser, R, Prijs, B, Sigel, H, Föry, W, Wright, LD & McCormick, DB (1970) Stability and structure of binary and ternary metal ion complexes with biocytin, the sulfoxide and sulfone, N–α–acetyl–L–lysine and L–alanine. Biochemistry 9, 32853293.Google Scholar
Griesser, R, Prijs, B, Sigel, H & McCormick, DB (1969) Binary and ternary Me2+ complexes with α – or β–substituted halogeno carboxylic acids. Inorganic and Nuclear Chemistry Letters 5, 951956.Google Scholar
Griesser, R, Sigel, H, Wright, LD & McCormick, DB (1973) Interactions of metal ions with biotin and biotin derivatives. Complexing and hydrogen-bond formation of the ureido group. Biochemistry 12, 19171922.CrossRefGoogle ScholarPubMed
Harrison, EH & McCormick, DB (1974) The metabolism of dl–[1,6–14C]lipoic acid in the rat. Archives of Biochemistry and Biophysics 160, 514522.Google Scholar
Horiike, K & McCormick, DB (1979) Correlations between biological activity and the number of functional groups chemically modified. Journal of Theoretical Biology 79, 381403.Google Scholar
Horiike, K & McCormick, DB (1980) Effect of ligand on chemical modification of proteins. Graphical determinations of dissociation constant and number of essential residues affected by ligand binding. Journal of Theoretical Biology 84, 691708.Google Scholar
Horiike, K, Merrill, AH Jr & McCormick, DB (1979) Activation and inactivation of rabbit liver pyridoxamine (pyridoxine) 5'–phosphate oxidase activity by urea and other solutes. Archives of Biochemistry and Biophysics 195, 325335.Google Scholar
Horiike, K, Tsuge, H & McCormick, DB (1979) Evidence for an essential histidyl residue at the active site of pyridoxamine (pyridoxine) 5'–phosphate oxidase from rabbit liver. Journal of Biological Chemistry 254, 66386643.Google Scholar
Howard, SC & McCormick, DB (1981) High–performance liquid chromatography of lipoic acid and analogues. Journal of Chromatography 208, 129131.Google Scholar
Im, WB, McCormick, DB & Wright, LD (1973) Bacterial degradation of biotin. Isolation and identification of d-allobisnorbiotin. Journal of Biological Chemistry 248, 77987805.Google Scholar
Im, WB, Roth, JA, McCormick, DB & Wright, LD (1970) Bacterial degradation of biotin. V. Metabolism of 14C–carbonyl–labeled biotin d–sulfoxide. Journal of Biological Chemistry 245, 62696273.Google Scholar
Innis, WSA, McCormick, DB & Merrill, AH Jr (1985) Variations in riboflavin binding by human plasma: Identification of immunoglobulins as the major proteins responsible. Biochemical Medicine 34, 151165.Google Scholar
Innis, WSA, Nixon, DW, Murray, DR, McCormick, DB & Merrill, AH Jr (1986) Immunoglobulins associated with elevated riboflavin binding by plasma from cancer patients. Proceedings of the Society for Experimental Biology and Medicine 181, 237241.Google Scholar
Iwahara, S, McCormick, DB, Wright, LD & Li, HC (1969) Bacterial degradation of biotin. III. Metabolism of 14C–carbonyl–labeled biotin. Journal of Biological Chemistry 244, 13931398.Google Scholar
Johnson, PG, Bell, AP & McCormick, DB (1975) Flavin–sensitized photooxidation of histidine. Photochemistry and Photobiology 21, 205208.Google Scholar
Johnson, PG & McCormick, DB (1973) Syntheses and properties of flavin–histidine peptides. Biochemistry 12, 33593364.Google Scholar
Joseph, T, Tsuge, H, Suzuki, Y & McCormick, DB (1996) Uptake and metabolism of pyridoxine 4'–α– and 5'–ß-D– glucosides by isolated rat liver cells. Journal of Nutrition 126, 28992903.Google Scholar
Kazarinoff, MN, Arsenis, C & McCormick, DB (1975) Preparation of FMN–cellulose and derivatives and FMN–agarose. Methods in Enzymology 34, 300302.Google Scholar
Kazarinoff, MN, Im, WB, Roth, JA, McCormick, DB & Wright, LD (1972) Bacterial degradation of biotin. VI. Isolation and identification of ß–hydroxy and ß–keto compounds. Journal of Biological Chemistry 247, 7583.CrossRefGoogle Scholar
Kazarinoff, MN & McCormick, DB (1973) N–(5'–Phospho–4'–pyridoxyl)amines as substrates for pyridoxine (pyridoxamine) 5'–phosphate oxidase. Biochemical and Biophysical Research Communications 52, 440446.Google Scholar
Kazarinoff, MN & McCormick, DB (1974) Specificity of pyridoxine (pyridoxamine) 5'–phosphate oxidase for flavin–phosphates. Biochimica et Biophysica Acta 359, 282287.CrossRefGoogle Scholar
Kazarinoff, MN & McCormick, DB (1975) Rabbit liver pyridoxamine (pyridoxine) 5'–phosphate oxidase: Purification and properties. Journal of Biological Chemistry 250, 34363442.Google Scholar
Kekelidze, TN, Edmondson, DE & McCormick, DB (1994) Flavin substrate specificity of the vitamin B2–aldehyde–forming enzyme from Schizophyllum commune. Archives of Biochemistry and Biophysics 315, 100103.CrossRefGoogle Scholar
Kekelidze, TN, Edmondson, DE & McCormick, DB (1995) Preparation of riboflavin specifically labeled in the 5'–hydroxymethyl terminus using a B2-aldehyde-forming enzyme from Schizophyllum commune. Journal of Labelled Compounds and Radiopharmaceuticals XXXVI, 953960.Google Scholar
Koster, JF, Veeger, C & McCormick, DB (1968) Photoreduction of amino acid oxidases in the presence of free flavin and the effect of urea. Biochimica et Biophysica Acta 153, 724726.Google Scholar
Kozik, A & McCormick, DB (1984) Mechanism of pyridoxine uptake by isolated rat liver cells. Archives of Biochemistry and Biophysics 229, 187193.Google Scholar
Lee, HM, McCall, NE, Wright, LD & McCormick, DB (1973) Urinary excretion of biotin and metabolites in the rat. Proceedings of the Society for Experimental Biology and Medicine 143, 642644.CrossRefGoogle Scholar
Lee, HM, Wright, LD & McCormick, DB (1972) The metabolism of carbonyl–labeled 14C–biotin in the rat. Journal of Nutrition 102, 14531464.Google Scholar
Lee, HM, Wright, LD & McCormick, DB (1973) Metabolism, in the rat, of biotin injected intraperitoneally as the avidin–biotin complex. Proceedings of the Society for Experimental Biology and Medicine 143, 438442.Google Scholar
Lee, S-S & McCormick, DB (1983) Effect of riboflavin status on hepatic activities of flavin–metabolizing enzymes in rats. Journal of Nutrition 113, 22742279.Google Scholar
Lee, S-S & McCormick, DB (1985) Thyroid hormone regulation of flavocoenzyme biosynthesis. Archives of Biochemistry and Biophysics 237, 197201.Google Scholar
Li, HC, McCormick, DB & Wright, LD (1968 a) Conversion of dethiobiotin to biotin in Aspergillus niger. Journal of Biological Chemistry 243, 64426445.Google Scholar
Li, HC, McCormick, DB & Wright, LD (1968 b) Metabolism of dethiobiotin in Aspergillus niger. Journal of Biological Chemistry 243, 43914395.Google Scholar
McCormick, DB (1961) Flavokinase of rat tissues and masking effect of phophatases. Proceedings of the Society for Experimental Biology and Medicine 107, 784786.CrossRefGoogle Scholar
McCormick, DB (1962) The intracellular|localization, partial purification, and properties of flavokinase from rat liver. Journal of Biological Chemistry 237, 959962.Google Scholar
McCormick, DB (1964) Specificity of flavin-adenine dinucleotide pyrophosphorylase for flavin phosphates and nucleotide triphosphates. Biochemical and Biophysical Research Communications 14, 493497.CrossRefGoogle Scholar
McCormick, DB (1964) Inhibition of flavin–adenine dinucleotide pyrophosphorylase by isoriboflavin. Nature 201, 925926.CrossRefGoogle ScholarPubMed
McCormick, DB (1965) Specific purification of avidin by column chromatography on biotin–cellulose. Analytical Biochemistry 13, 194198.Google Scholar
McCormick, DB (1968 a) Nature of the intramolecular complex of flavine adenine di-nucleotide. In Molecular Associations in Biology, pp. 377392 [Pullman, D editor]. New York: Academic Press.Google Scholar
McCormick, DB (1968 b) Photochemical reactions of FAD and FAD–dependent flavoproteins. In Flavins and Flavin Enzymes, pp. 154163 [Yagi, K editor]. Tokyo: University of Tokyo Press.Google Scholar
McCormick, DB (1969) Chemical syntheses and biocytinase specificity for sulfoxides and sulfone of d–biotin. Proceedings of the Society for Experimental Biology and Medicine 132, 502504.CrossRefGoogle Scholar
McCormick, DB (1970) The tryptophans in flavodoxin and synthetic flavinyl peptides characterized by chemical and photochemical oxidations. Experientia 26, 243244.Google Scholar
McCormick, DB (1975 a) Biotin. Nutrition Reviews 33, 97102.Google Scholar
McCormick, DB (1975 b) Metabolism of riboflavin. In Riboflavin, pp. 153198 [Rivlin, RS editor]. New York: Plenum Press.Google Scholar
McCormick, DB (1976 a) Riboflavin. In Present Knowledge in Nutrition. 4th ed., pp. 131140 [Hegsted, DM editor]. New York: The Nutrition Foundation.Google Scholar
McCormick, DB (1976 b) Biotin. In Present Knowledge in Nutrition. 4th ed., pp. 217225 [Hegsted, DM editor]. New York: The Nutrition Foundation.Google Scholar
McCormick, DB (1977 a) Interactions of flavins with amino acid residues: Assessments from spectral and photochemical studies. Photochemistry Photobiology 26, 169182.Google Scholar
McCormick, DB (1977 b) Spectral and photochemical assessments of interactions of the flavin ring system with amino acid residues. In 10th Jerusalem Symposium: Excited States in Organic Chemistry and Biochemistry, pp. 233245 [Pullman, B and Goldblum, N editors]. Dordrecht: Reidel Publishing Co.CrossRefGoogle Scholar
McCormick, DB (1989) Application of new techniques in nutrition research: An example with riboflavin. In Nutrition, Health|Promotion, and Chronic Disease Prevention: International Perspective, pp. 555563 [Palmer, S, Peter, FM, Eckhardt, S and Schoket, Z editors]. Budapest: Skala.Google Scholar
McCormick, DB (1994) Vitamin B6 transport and metabolism: Clues for delivery of bio–active compounds. In Biochemistry of Vitamin B6 and PQQ, pp. 311317 [Marino, G, Sannia, G and Bossa, F editors]. Basel:Birkhauser.Google Scholar
McCormick, DB (2000) A trail of research on cofactors: An odyssey with friends. Journal of Nutrition 130, 323S330S.Google Scholar
McCormick, DB (2001) Vitamin B-6. In. In Present Knowledge in Nutrition. 8th ed., pp. 207213 [Bowman, BA and Russell, y editors]. Washington, D: ILSI Press.Google Scholar
McCormick, DB, Arsenis, C & Hemmerich, P (1963) Specificity of liver flavokinase for 9–(1'–D-ribityl)isoalloxazines variously substituted in positions 2, 6 and 7. Journal of Biological Chemistry 238, 30953099.Google Scholar
McCormick, DB & Bowers-Komro, DM (1986) Stereochemistry of pyridoxamine 5'– phosphate oxidase. In Mechanisms of Enzymatic Reactions: Stereochemistry.p. 336 [Frey, PA editor]. New York: Elsevier.Google Scholar
McCormick, DB, Bowers-Komro, DM, Bonkovsky, J, Larson, C & Zhang, Z (1991) Characteristics of a transporter for uptake of vitamin B6 into mammalian cells. In Enzymes Dependent on Pyridoxal Phosphate and Other Carbonyl Compounds as Cofactors, pp. 609611 [Fukui, T, Kagamiyama, H, Soda, K & Wada, H editors]. New York: Pergamon Press.Google Scholar
McCormick, DB & Butler, RC (1962) Substrate specificity of liver flavokinase. Biochimica et Biophysica Acta 65, 326332.Google Scholar
McCormick, DB, Chassy, BM & Tsibris, JCM (1964) Coenzyme specificity of D–amino acid oxidase for the adenylate moiety of FAD. Biochimica et Biophysica Acta 89, 447452.Google ScholarPubMed
McCormick, DB & Chen, H (1999) Update on interconversions of vitamin B–6 with its co–Enzyme. Journal of Nutrition 129, 325327.Google Scholar
McCormick, DB, Falk, MC, Rizzuto, F & Tollin, G (1975) Inter– and intramolecular effects of tyrosyl residues on flavin triplets and radicals as investigated by flash photolysis. Photochemistry and Photobiology 22, 175182.CrossRefGoogle ScholarPubMed
McCormick, DB, Gregory, ME & Snell, EE (1961) Pyridoxal phosphokinases. I. Assay, distribution, purification, and properties. Journal of Biological Chemistry 236, 20762084.Google Scholar
McCormick, DB, Griesser, R & Sigel, H (1974) Metal ion-thioether interactions of biological interest. In Metal Ions in Biological Systems, pp vol. 1: pp. 213246 [Sigel, H editor]. New York: Marcel Dekker.Google Scholar
McCormick, DB, Guirard, BM & Snell, EE (1960) Comparative inhibition of pyridoxal kinase and glutamic acid decarboxylase by carbonyl reagents. Proceedings of the Society for Experimental Biology and Medicine 104, 554557.CrossRefGoogle Scholar
McCormick, DB, Innis, WSA, Merrill, AH Jr, Bowers-Komro, DM, Oka, M & Chastain, JL (1988) An update on flavin metabolism in rats and humans. In Flavins and Flavoproteins, pp. 459471 [ Edmondson, DE and McCormick, DB editors]. New York: Walter de Gruyter.Google Scholar
McCormick, DB, Innis, WJA, Merrill, AH Jr & Lee, S-S (1984) Mammalian metabolism of flavins. In Flavins and Flavoproteins, pp 833846 [Grey, RC, Engel, PC and Mayhew, SG editors]. New York: Walter de Gruyten.CrossRefGoogle Scholar
McCormick, DB, Kazarinoff, MN & Tsuge, H (1976) FMN–dependent pyridoxine (pyridoxamine) 5'–phosphate oxidase from rabbit liver. In Flavins and Flavoproteins, pp. 708719 [Singer, TP editor]. New York: Walter de Gruyter.Google Scholar
McCormick, DB, Koster, JF & Veeger, C (1967) On the mechanisms of photochemical reductions of FAD and FAD–dependent enzymes. European Journal of Biochemistry 2, 387391.Google Scholar
McCormick, DB & Merrill, AH Jr (1980) Pyridoxamine (pyridoxine) 5'–phosphate Oxidase. In Vitamin B6 Metabolism and Role in Growth, pp. 126 [Tryfiates, GP editor]. Westport, CT: Food and Nutrition Press.Google Scholar
McCormick, DB, Oka, M, Bowers-Komro, DM, Yamada, Y & Hartman, H (1997) Purification and properties of FAD synthetase from liver. Methods in Enzymology 280, 407413.CrossRefGoogle ScholarPubMed
McCormick, DB & Olson, RE (1984) Biotin. In Present Knowledge in Nutrition. 5th ed., pp. 365376 [Olson, RE editor]. Washington, DC: The Nutrition Foundation.Google Scholar
McCormick, DB & Roth, JA (1970) Specificity, stereochemistry and mechanism of the colour reaction between p–dimethylaminocinnamaldehyde and biotin analogues. Analytical Biochemistry 34, 226236.Google Scholar
McCormick, DB & Russell, M (1962) Hydrolysis of flavin mononucleotide by acid phosphatases from animal tissues. Comparative Biochemistry and Physiology 5, 113121.Google Scholar
McCormick, DB, Sigel, H & Wright, LD (1969) Structure of Mn2+ and Cu2+ complexes with L–methionine, S–methyl–L–cysteine, L–threonine, and L–serine. Biochimica et Biophysica Acta 184, 318328.Google Scholar
McCormick, DB & Snell, EE (1959) Pyridoxal kinase of human brain and its inhibition by hydrazine derivatives. Proceedings of the National Academy of Sciences 45, 13711379.Google Scholar
McCormick, DB & Snell, EE (1961) Pyridoxal phosphokinases. II. Effects of inhibitors. Journal of Biological Chemistry 236, 20852088.CrossRefGoogle ScholarPubMed
McCormick, DB, Suttie, JW & Wagner, C (editors) (1997) In Vitamins and Coenzymes. Methods in Enzymology. pp vols. 279, 280, 281, 282. Orlando, FL: Academic Press.Google Scholar
McCormick, DB & Tu, SC (1970 a) Colorimetric determination of tyrosine in the presence of flavin. Analytical Biochemistry 37, 215219.Google Scholar
McCormick, DB & Wright, LD (1970 b) The metabolism of biotin and its analogues. In Comprehensive Biochemistry. pp vol. 21: pp. 81110 [Florkin, M and Stotz, EH editors]. Amsterdam: Elsevier.Google Scholar
MacKenzie, RE, Föry, W & McCormick, DB (1969) Flavinyl peptides. II. Intramolecular interactions in flavinyl– aromatic amino acid peptides. Biochemistry 8, 18391844.Google Scholar
Merrill, AH Jr, Addison, R & McCormick, DB (1978) Induction of hepatic and intestinal flavokinase after oral administration of riboflavin to riboflavin–deficient rats. Proceedings of the Society for Experimental Biology and Medicine 158, 572574.CrossRefGoogle ScholarPubMed
Merrill, AH Jr, Froehlich, JA & McCormick, DB (1979) Purification of riboflavin– binding proteins from bovine plasma and discovery of a pregnancy-specific riboflavin-binding protein. Journal of Biological Chemistry 254, 93629364.CrossRefGoogle ScholarPubMed
Merrill, AH Jr, Froehlich, JA & McCormick, DB (1981) Isolation and identification of alternative riboflavin–binding proteins from human plasma. Biochemical Medicine 25, 198206.Google Scholar
Merrill, AH Jr, Horiike, K & McCormick, DB (1978) Evidence for the regulation of pyridoxal 5'–phosphate formation in liver by pyridoxamine (pyridoxine) 5'–phosphate oxidase. Biochemical and Biophysical Research Communications 83, 984990.Google Scholar
Merrill, AH Jr, Kasai, S, Matsui, K, Tsuge, H & McCormick, DB (1979) Spectroscopic studies of pyridoxamine (pyridoxine) 5'–phosphate oxidase. Equilibrium dissociation constants and spectra for riboflavin 5'–phosphate and analogs. Biochemistry 18, 36353641.CrossRefGoogle Scholar
Merrill, AH Jr, Korytnyk, W, Horiike, K & McCormick, DB (1980) Spectroscopic studies of complexes between pyridoxamine (pyridoxine) 5'–phosphate oxidase and pyridoxyl 5'–phosphate compounds differing at position 4′. Biochimica et Biophysica Acta 626, 5763.Google Scholar
Merrill, AH Jr, Lambeth, JD, Edmondson, DE & McCormick, DB (1981) Formation and mode of action of flavoproteins. Annual Review of Nutrition 1, 281317.Google Scholar
Merrill, AH Jr & McCormick, DB (1978) Flavin affinity chromatography: General methods for purification of proteins that bind riboflavin. Analytical Biochemistry 89, 87102.Google Scholar
Merrill, AH Jr & McCormick, DB (1979) Preparation and properties of immobilized flavokinase. Biotechnology and Bioengineering XXI, 243252.Google Scholar
Merrill, AH Jr & McCormick, DB (1980) Affinity chromatographic purification and properties of flavokinase (ATP: riboflavin 5'–phosphotransferase) from rat liver. Journal of Biological Chemistry 255, 13351338.Google Scholar
Merrill, AH Jr, Shapira, G & McCormick, DB (1982) Recent findings concerning mammalian riboflavin–binding proteins. In Flavins and Flavoproteins. , pp. 508513 [Massey, V and Williams, CH Jr editors]. New York: Elsevier Biomedical.Google Scholar
Nakano, H, Hartman, H & McCormick, DB (1992) Mammalian flavokinase and FAD synthetase: Functions of divalent metal ions and arginyl residues in the anionic substrate sites. In 1st International Congress on Vitamins and Biofactors in Life Science , pp. 450452 [Kobayashi, T editor]. Osaka: Center for Academic Publications.Google Scholar
Nakano, H & McCormick, DB (1991 a) Rat brain flavokinase:|purification, properties, and comparison to the enzyme from liver and small intestine. In Flavins and Flavoproteins, pp. 8992 [Curti, B, Ronchi, S and Zanetti, G editors]. New York: Walter de Gruyter.Google Scholar
Nakano, H & McCormick, DB (1991 b) Stereospecificity of the metal-ATP complex in flavokinase from rat small intestine. Journal of Biological Chemistry 266, 2212522128.Google Scholar
Nakano, H & McCormick, DB (1992) Modification of arginyl and lysyl residues in flavo-kinase from rat small intestine. Biochemistry International 28, 441450.Google ScholarPubMed
Ogunmodede, BK & McCormick, DB (1966) Sparing of riboflavin in rats by 6,7–dimethyl–9–(ω–hydroxyalkyl)isoalloxazines. Proceedings of the Society for Experimental Biology and Medicine 122, 845847.Google Scholar
Oka, M & McCormick, DB (1985) Urinary lumichrome-level catabolites of riboflavin are due to microbial and photochemical events and not tissue enzymic cleavage of the ribityl chain. Journal of Nutrition 115, 496499.Google Scholar
Oka, M & McCormick, DB (1987) Complete purification and general characterization of FAD synthetase from rat liver. Journal of Biological Chemistry 262, 74187422.Google Scholar
Pritchard, AB, McCormick, DB & Wright, LD (1967) Optical rotatory dispersion studies on the heat denaturation of avidin and the avidin–biotin complex. Biochemical and Biophysical Research Communications 25, 524528.Google Scholar
Rasmussen, KM, Barsa, PM & McCormick, DB (1979) Pyridoxamine (pyridoxine) 5'–phosphate oxidase activity in rat tissues during development of riboflavin or pyridoxine deficiency. Proceedings of the Society for Experimental Biology and Medicine 161, 527530.Google Scholar
Rasmussen, KM, Barsa, PM, McCormick, DB & Roe, DA (1980) Effect of strain, sex and dietary riboflavin on pyridoxamine (pyridoxine) 5'–phosphate oxidase activity in rat tissues. Journal of Nutrition 110, 19401946.Google Scholar
Roth, JA, Chassy, BM & McCormick, DB (1966) Coenzymatic activities of 2–anilino and 2–morpholino derivatives of FMN with yeast NADPH diaphorase. Biochimica et Biophysica Acta 118, 429431.CrossRefGoogle ScholarPubMed
Roth, JA & McCormick, DB (1967) Complexing of riboflavin and its 2–substituted analogues with adenosine and other 6–substituted purine derivatives. Photochemistry and Photobiology 6, 657664.Google Scholar
Roth, JA, McCormick, DB & Wright, LD (1970) Bacterial degradation of biotin. IV. Metabolism of 14C–carbonyl–labeled biotin l–sulfoxide. Journal of Biological Chemistry 245, 62646268.CrossRefGoogle Scholar
Roughead, ZK & McCormick, DB (1990 a) A qualitative and quantitative assessment of flavins in cows milk. Journal of Nutrition 120, 382388.Google Scholar
Roughead, ZK & McCormick, DB (1990 b) Flavin composition of human milk. American Journal of Clinical Nutrition 52, 854857.Google Scholar
Roughead, ZK & McCormick, DB (1991) Urinary riboflavin and its metabolites: Effects of riboflavin supplementation in healthy residents of rural Georgia (USA). European Journal of Clinical Nutrition 45, 299307.Google ScholarPubMed
Rucker, RB, Suttie, JW, McCormick, DB & Machlin, LJ (editors) (2001) In Handbook of Vitamins, pp : 3rd ed. New York: Marcel Dekker.Google Scholar
Ruis, H, Brady, RN, McCormick, DB & Wright, LD (1968) Bacterial degradation of biotin. II. Catabolism of 14C–homobiotin and 14C–norbiotin. Journal of Biological Chemistry 243, 547551.Google Scholar
Sander, EG, McCormick, DB & Wright, LD (1966) Column chromatography of nucleotides over thymidylate–cellulose. Journal of Chromatography 21, 419423.Google Scholar
Sander, EG, Wright, LD & McCormick, DB (1965) Evidence for function of metal ion in the activity of dihydroorotase from Zymobacterium oroticum. Journal of Biological Chemistry 240, 36283630.Google Scholar
Schneider, G & Lindqvist, Y (1997) Structure of ATP–dependent carboxylase, dethiobiotin synthase. Methods in Enzymology 279, 376385.Google Scholar
Shiga, K, Tollin, G, Falk, MC & McCormick, DB (1975 a) Binding and oxidation–reduction of monoamine oxidase–type 8α-(S–peptidyls) flavins with Azotobacter (Shethna) flavodoxin. Biochemical and Biophysical Research Communications 66, 227234.Google Scholar
Shih, JCH, Rozo, ML, Wright, LD & McCormick, DB (1975 b) Characterization of the growth of Pseudomonas putida LP on lipoate and its analogues: Transport, oxidation, sulphur source, and enzyme induction. Journal of General Microbiology 86, 217227.Google Scholar
Shih, JCH, Williams, PB, Wright, LD & McCormick, DB (1974) Properties of lipoic acid analogs. Journal of Heterocyclic Chemistry 11, 119123.Google Scholar
Shih, JCH, Wright, LD & McCormick, DB (1972) Isolation, identification and characterization of a lipoate–degrading pseudomonad and of a lipoate catabolite. Journal of Bacteriology 112, 10431051.Google Scholar
Sigel, H (editor) (1974) In Metal Ions in Biological Systems. vol. 1: Simple complexes. New York: Marcel Dekker.Google Scholar
Sigel, H, Becker, K & McCormick, DB (1967) Ternary complexes in solution. Influence of 2,2'–bipyridyl on the stability of 1:1 complexes of Co2+, Ni2+, Cu2+, and Zn2+ with hydrogen phosphate, adenosine 5'–monophosphate, and adenosine 5'–triphosphate. Biochimica et Biophysica Acta 148, 655664.Google Scholar
Sigel, H, Griesser, R & McCormick, DB (1969) On the structure of manganese(II)– and copper(II)–histidine complexes. Archives of Biochemistry and Biophysics 134, 217227.Google Scholar
Sigel, H, Griesser, R & McCormick, DB (1972) Ternary complexes in solution. XIII. Mixed-ligand complexes of copper(II) or zinc(II) with 2,2'–bipyridyl and thioether carboxylates or some of their sulfoxide or sulfone derivatives. Inorganica Chimica Acta 6, 559563.Google Scholar
Sigel, H, Griesser, R, Prijs, B, McCormick, DB & Joiner, M (1969) ‘Hard and soft’ behavior of Mn2+, Cu2+ and Zn2+ with respect to carboxylic acids and α–oxy– or α–thio–substituted carboxylic acids of biochemical significance. Archives of Biochemistry and Biophysics 130, 514520.CrossRefGoogle ScholarPubMed
Sigel, H & McCormick, DB (1971) The structure of the Cu2+ L-histidine 1:2 complex in solution. Journal of the American Chemical Society 93, 20412044.Google Scholar
Sigel, H & McCormick, DB (1974) On the discriminating behavior of metal ions and ligands with regard to their biological significance. In Collected Accounts of Transition Metal Chemistry. [Bunnett, JF editor]. Washington, DC: American Chemical Society.Google Scholar
Sigel, H, McCormick, DB, Griesser, R, Prijs, B & Wright, LD (1969) Metal ion complexes with biotin and biotin derivatives. Participation of sulfur in the orientation of divalent cations. Biochemistry 8, 26872695.Google Scholar
Sigel, H, MacKenzie, RE & McCormick, DB (1970) On the structure of copper(II)–histidine complexes. Biochimica et Biophysica Acta 200, 411413.Google Scholar
Sigel, H, Neumann, CF, Prijs, B, McCormick, DB & Falk, MC (1977) Influence of alkyl side chains with hydroxy or thioether groups on the stability of binary and ternary copper(II)–dipeptide complexes. Inorganic Chemistry 16, 790796.Google Scholar
Sigel, H, Prijs, B & McCormick, DB (1978) Stability and structure of Cd2+ and Pb2+ com–plexes with biotin, lipoic|acid, and some of their derivatives in solution. Journal of Inorganic and Nuclear Chemistry 40, 16781680.Google Scholar
Sigel, H, Prijs, B, McCormick, DB & Shih, JCH (1978) Stability and structure of binary and ternary complexes of α-lipoate and lipoate derivatives with Mn2+, Cu2+ and Zn2+ in solution. Archives of Biochemistry and Biophysics 187, 208214.CrossRefGoogle ScholarPubMed
Spence, JT & McCormick, DB (1976) Lipoic acid metabolism in the rat. Archives of Biochemistry and Biophysics 174, 1319.Google Scholar
Tepper, JP, McCormick, DB & Wright, LD (1966) Direct evidence for the conversion of dethiobiotin to biotin in 241. In Aspergillus niger. Journal of Biological Chemistry. 241 57345735.Google Scholar
Tsibris, JCM, McCormick, DB & Wright, LD (1965) Studies on the donor–acceptor complexes relating to the intramolecular association of the riboflavin and adenosine moieties of flavin–adenine dinucleotide. Biochemistry 4, 504509.Google Scholar
Tsibris, JCM, McCormick, DB & Wright, LD (1966) Studies on the binding and function of flavin phosphates with flavin mononucleotide–dependent enzymes. Journal of Biological Chemistry 241, 11381143.Google Scholar
Tsuge, H & McCormick, DB (1980) Reactivity of the sulfhydryl groups in pyridoxamine phosphate oxidase from liver. In Flavins and Flavoproteins, pp. 517527 [Yagi, K and Yamano, T editors]. Tokyo: Japan Scientific Society Press.Google Scholar
Tu, SC & McCormick, DB (1969) The biological activity and excretion of 6,7–dimethyl– 9–(ω–carboxyalkyl)isoalloxazines in rats. Journal of Nutrition 97, 307310.CrossRefGoogle Scholar
Tu, SC & McCormick, DB (1972) Insolubilized D-amino acid oxidase: Properties and potential use. Separation Science 7, 403407.Google Scholar
Tu, SC & McCormick, DB (1973) Photoinactivation of porcine D–amino acid oxidase with flavin–adenine dinucleotide. Journal of Biological Chemistry 248, 63396347.Google Scholar
Tu, SC & McCormick, DB (1974) Conformation of porcine D–amino acid oxidase as studied by protein fluorescence and optical rotatory dispersion. Biochemistry 13, 893899.Google Scholar
Visser, J, McCormick, DB & Veeger, C (1968) Relation between conformation and activities of lipoamide dehydrogenase. II. Some aspects of recombination with FAD analogues. Biochimica et Biophysica Acta 159, 257264.Google Scholar
Walker, FA, Sigel, H & McCormick, DB (1972) Spectral properties of mixed-ligand copper(II) complexes and their corresponding binary parent complexes. Inorganic Chemistry 11, 27562763.Google Scholar
Westendorf, J & McCormick, DB (1980) Isolation of volatile sulfur-containing microbial catabolites of biotin. International Journal of Vitamin and Nutrition Research 50, 6265.Google Scholar
Winkler, ME (2000) Genetic and genomic approaches for delineating the pathway of. In pyridoxal 5'–phosphate coenzyme biosynthesis in Escherichia coli. In biochemistry and Molecular Biology of Vitamin B6 and PQQ–dependent Proteins. pp 310. : [Iriarte, AKagan, HM and Martinez–Carrion, M editors]. Basel: Birkhauser.Google Scholar
Wu, FYH & McCormick, DB (1971 a) The fluorescence quenching of aromatic amino acids and flavin portions of flavinyl peptides. 229. In Biochimica et Biophysica Acta. 236 440443.Google Scholar
Wu, FYH & McCormick, DB (1971 b) Flavin–sensitized photooxidations of tryptophan and tyrosine. Biochimica et Biophysica Acta 236, 479483.Google Scholar
Wu, FYH, Tu, SC, Wu, WC & McCormick, DB (1970) Characteristics of the fluorescence spectra of apoenzyme and flavin portions of D–amino acid oxidase. Biochemical and Biophysical Research Communications 41, 381385.Google Scholar
Yamada, Y, Merrill, AH Jr & McCormick, DB (1990) Probable reaction mechanisms of flavokinase and FAD synthetase from rat liver. Archives of Biochemistry and Biophysics 278, 125130.Google Scholar
Yang, CS, Arsenis, CS & McCormick, DB (1964) Microbiological and enzymatic assays of riboflavin analogues. Journal of Nutrition 84, 167172.Google Scholar
Yang, CS & McCormick, DB (1967 a) Substrate specificity of riboflavin hydrolase from Pseudomonas riboflavina. Biochimica et Biophysica Acta 132, 511513.Google Scholar
Yang, CS & McCormick, DB (1967 b) Degradation and excretion of riboflavin in the rat. Journal of Nutrition 93, 445453.Google Scholar
Zempleni, J, Galloway, JR & McCormick, DB (1996 a) Pharmacokinetics of orally and intravenously administered riboflavin in healthy humans. American Journal of Clinical Nutrition 63, 5466.Google Scholar
Zempleni, J, Galloway, JR & McCormick, DB (1996 b) The identification and kinetics of 7α–hydroxyriboflavin (7–hydroxymethylriboflavin) in blood plasma from humans following oral administration of riboflavin supplements. International Journal of Vitamin and Nutrition Research 66, 151157.Google Scholar
Zempleni, J, Galloway, JR & McCormick, DB (1996 c) The metabolism of riboflavin in female patients with liver cirrhosis. International Journal of Vitamin and Nutrition Research 66, 237243.Google Scholar
Zempleni, J, McCormick, DB & Mock, DM (1996 d) The identification of biotin sulfone, bisnorbiotin methyl ketone, and tetranorbiotin–l–sulfoxide in human urine. American Journal of Clinical Nutrition 65, 508511.Google Scholar
Zempleni, J, McCormick, DB, Stratton, SL & Mock, DB (1996 e) Lipoic acid (thioctic acid) analogs, tryptophan|analogs, and urea do not interfere with the assay of biotin and biotin metabolites by high–performance liquid chromatography/avidin–binding assay. Journal of Nutritional Biochemistry 7, 518523.Google Scholar
Zhang, Z, Gregory, J E III & McCormick, DB (1993 a) Uptake and metabolism of pyridoxine–5'–β-D–glucoside by isolated rat liver cells. Journal of Nutrition 123, 8589.CrossRefGoogle ScholarPubMed
Zhang, Z & McCormick, DB (1991) Uptake of N–(4'–pyridoxyl)amines and release of amines by renal cells: A model for transporter–enhanced delivery of bioactive compounds. Proceedings of the National Academy of Sciences 88, 1040710410.Google Scholar
Zhang, Z & McCormick, DB (1992 a) Uptake and metabolism of N–(4'–pyridoxyl)amines by isolated rat liver cells. Archives of Biochemistry and Biophysics 294, 394397.Google Scholar
Zhang, Z & McCormick, DB (1992 b) Uptake and metabolism of 4′N–substituted pyridoxamines by cells from the liver and kidneys of rats. In 1st International Congress on Vitamin and Biofactors in Life Science. pp 208211. [Kobayashi, T editor]. Osaka: Center for Academic Publications.Google Scholar
Zhang, Z, Smith, E, Surowiec, SM, Merrill, AH Jr & McCormick, DB (1993 b) Synthesis of N–(4'–pyridoxyl)–sphingosine and its uptake and metabolism by isolated cells. Membrane Biochemistry 10, 5359.Google Scholar