The Sialic Acids

作者：F. Dodyk Kundig, David Aminoff, Saul Roseman · 发表于：Journal of Biological Chemistry · 年份：1971 · DOI：10.1016/s0021-9258(18)62323-3 · 被引用次数：196 · 研究领域：Glycosylation and Glycoproteins Research、Carbohydrate Chemistry and Synthesis、Biochemical and Molecular Research

Abstract Partial purification of an Escherichia coli sialyltransferase (CMP-N-acetylneuraminic acid-colominic acid sialyltransferase) that transfers N-acetylneuraminic acid (N-AN) from cytidine 5'-monophospho-N-acetylneuraminic acid to colominic acid has been achieved. The enzyme was detected in a particulate fraction. Kinetics of the reaction have been studied and the substrate specificity is discussed. Both endogenous colominic acid, bound to the enzyme fraction, and purified, soluble exogenous colominic acid acted as N-AN acceptors, the endogenous acceptor being much more effective. The presence of 1.2 m ammonium sulfate yielded a 4-fold increase of N-AN incorporation into the endogenous colominic acid, and was required for N-AN incorporation into the soluble exogenous colominic acid. The available data suggest that chain elongation proceeds at the nonreducing termini of the polymer, comparable to the formation of glycogen, rather than at the reducing end, as in the case of the bacterial lipopolysaccharides.