ABSTRACT
Changes in the structure of the N-acyl group in N-acylated amino acid derivatives significantly affect both the recognition and activity of penicillin acylases on this series of substrates. However, penicillin acylases from both Alcaligenes faecalis and Escherichia coli are capable of removing the N-benzyloxycarbonyl protecting group in amino acid derivatives under mild conditions without the use of toxic reagents. Efficiency in using penicillin acylases in preparative organic synthesis can be improved by utilizing modern rational enzyme design methods.
ABSTRACT
The possibility of using amides of halogen-substituted acetic acids as acyl donors in penicillin acylase-catalyzed reactions has been investigated, and the ability of this group of compounds to inactivate enzymes in the course of the catalytic conversion has been established. The strongest inactivating effect was demonstrated by iodoacetamide and bromoacetamide. However, the negative contribution of this side activity can be minimized by decreasing the temperature, when the rate of acyl donor conversion by penicillin acylases is still high enough, but the impact of enzyme inactivation becomes less significant. The catalytic activity of penicillin acylase from Alcaligenes faecalis in the conversion of 2-haloacetamides was significantly (5-8 times) higher than that of penicillin acylase from Escherichia coli.
ABSTRACT
The results of planned population surveys for opisthorchiasis performed by teams of epidemiologists in 11 districts of Chernigov Province have been reviewed. 130,067 individuals in 156 communities have been examined. All the communities were situated not more than 5 km from the main water artery of the area--the Desna River and its main tributaries--the Seim, the Ubed', the Doch', the Borzna. 713 cases of opisthorchiasis have been identified in 96 villages. 1.0 +/- 0.2% (out of 3,180) of mollusks C. inflata and 0.9 +/- 0.4% of carps from the river basins in 8 districts of the region proved to be invaded with Opisthorchis larvae.
