Cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMP-NeuAc hydroxylase) participates in the hydroxylation reaction of CMP-NeuAc to form CMP-N- glycolylneuraminic acid (CMP-NeuGc). The hydroxylation is carried out by an enzyme complex composed of cytochrome b5, NADH cytochrome b5 reductase, and CMP-NeuAc hydroxylase in the presence of NADH. Other characteristic features of the hydroxylation are that (1) the reaction is a rate-limiting step for the expression of NeuGc; (2) CMP-NeuAc hydroxylase is a soluble and cytosolic protein, but the other enzymes, cytochrome b5 and NADH cytochrome b5 reductase, are endoplasmic reticulum (ER) membrane-bound proteins; and (3) the expression of NeuGc is tissue- and species-specific, and both phenotypes are regulated by CMP-NeuAc hydroxylase.
KeywordsSialic Acid Microsomal Fraction Acid Hydroxylation Acid Hydroxylase D86324 AF074480
Unable to display preview. Download preview PDF.
- Corfield AP, Schauer R (1982) Metabolism of sialic acid. In: Schauer R (ed) Sialic acids, chemistry, metabolism and function. Springer Berlin Heidelberg, New York, pp 196–261Google Scholar
- Kawano T, Koyama S, Takematsu H, Kozutsumi Y, Kawasaki H, Kawashima S, Kawasaki T, Suzuki A (1995) Molecular cloning of cytidine-monophosho-N-acetylneuraminic acid hydroxylase: regulation of species-and tissue-specific expression of N-glycolylneuraminic acid. J Biol Chem 270:16458–16463PubMedCrossRefGoogle Scholar
- Koyama S, Yamaji T, Takematsu H, Kawano T, Kozutsumi Y, Suzuki A, Kawasaki T (1996) A naturally occurring 46-amino acid deletion of cytidine monophospho-N-acetylneuraminic acid hydroxylase leads to a change in the intracellular distribution of the protein. Glycoconjugate J 13:353–358CrossRefGoogle Scholar
- Shaw L, Schauer R (1988) Detection of CMP-N-acetylneuraminic acid hydroxylase activity in fractionated mouse liver. Biochem J 263:355–364Google Scholar
- Takematsu H, Kawano T, Koyama S, Kozutsumi Y, Suzuki A, Kawasaki T (1994) Reaction mechanism underlying CMP-N-acetylneuraminic acid hydroxylation in mouse liver: formation of a ternary complex of cytochrome b5, CMP-N-acetylneuraminic acid, and a hydroxylation enzyme. J Biochem 115:381–386PubMedGoogle Scholar