Biochemical Journal 1986-04-01

Streptomyces K15 DD-peptidase-catalysed reactions with suicide beta-lactam carbonyl donors.

M Leyh-Bouille, M Nguyen-Distèche, S Pirlot, A Veithen, C Bourguignon, J M Ghuysen

Index: Biochem. J. 235(1) , 177-82, (1986)

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Abstract

The values of the kinetic parameters that govern the interactions between the Streptomyces K15 DD-peptidase and beta-lactam compounds were determined by measuring the inactivating effect that these compounds exert on the transpeptidase activity of the enzyme and, in the case of [14C]benzylpenicillin and [14C]cefoxitin, by measuring the amounts of acyl-enzyme formed during the reaction. K15 DD-peptidase binds benzylpenicillin or cefoxitin at a molar ratio of 1:1. Benzylpenicilloate is the major product released during breakdown of the acyl-enzyme formed with benzylpenicillin. Benzylpenicillin is not a better acylating agent than the amide Ac2-L-Lys-D-Ala-D-Ala and ester Ac2-L-Lys-D-Ala-D-lactatecarbonyl-donor substrates. beta-Lactam compounds possessing a methoxy group on the alpha-face of the molecule show high inactivating potency.