engleski

Comparison of mammalian serum esterases hydrolyzing acylated monosaccharides

Esterases of different specifity and activity are present in mammalian sera. In our previous studies we have described and characterized the esterases which could be used for deacylation of pivaloylated and acylated monosaccharides. The aim of the present study was to compare the activities of esterases originating from different mammals, as well as human serum. The deacylation was monitored throughout the experiments using methyl 2, 6-di-O- pivaloyl-a-D-(U-14C)glucopyranoside (2, 6-DP)as the representative substrate. Rabbit and guinea pig sera exhibited high esterase activities (characterized as carboxyl esterases). More detailed chromatgraphic analysis revealed the marked difference between these two sources ; rabbit serum contained one major peak which preferentially hydrolysed 6-O-pivaloyl group in 2, 6-DP, while in guinea pig serum two prominent peaks of activity were detected and one preferentially hydrolysed 2-O-pivaloyl group. Even more striking difference was noticed when human and sheep sera were examined, since the major event observed was the migration of 2-O-pivaloyl group to the position 4- in the sugar molecule, followed by very slow deesterification.

mammalian serum ; esterases ; monosaccharides

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