Streptomyces K15 DD-peptidase-catalysed reactions with ester and amide carbonyl donors

In water, the purified 26 000-Mr membrane-bound DD-peptidase of Streptomyces K15 hydrolyses the ester carbonyl donor Ac2-L-Lys-D-Ala-D-lactate (release of D-lactate) and the amide carbonyl donor Ac2-L-Lys-D-Ala-D-Ala (release of D-alanine) with accumulation of acyl- (Ac2-L-Lys-D-alanyl-)enzyme. Wher...

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Bibliographic Details
Published in:Biochemical journal 1986-04, Vol.235 (1), p.167-176
Main Authors: Nguyen-Distèche, M, Leyh-Bouille, M, Pirlot, S, Frère, J M, Ghuysen, J M
Format: Article
Language:English
Subjects:
Acylation
Biochemistry, biophysics & molecular biology
Biochimie, biophysique & biologie moléculaire
Carboxypeptidases - metabolism
cell membranes
D-alanine
D-Amino-Acid Oxidase - pharmacology
Dipeptides - metabolism
Hydrolysis
Kinetics
Lactates - metabolism
lactic acid
Life sciences
Microbiologie
Microbiology
Muramoylpentapeptide Carboxypeptidase - metabolism
Oligopeptides - metabolism
Penicillin G - metabolism
peptidase
Sciences du vivant
Streptomyces
Streptomyces - enzymology
Substrate Specificity
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Summary:In water, the purified 26 000-Mr membrane-bound DD-peptidase of Streptomyces K15 hydrolyses the ester carbonyl donor Ac2-L-Lys-D-Ala-D-lactate (release of D-lactate) and the amide carbonyl donor Ac2-L-Lys-D-Ala-D-Ala (release of D-alanine) with accumulation of acyl- (Ac2-L-Lys-D-alanyl-)enzyme. Whereas hydrolysis of the ester substrate proceeds to completion, hydrolysis of the amide substrate is negligible because of the capacity of the K15 DD-peptidase for utilizing the released D-alanine in a transfer reaction (Ac2-L-Lys-D-Ala-D-Ala + D-Ala---Ac2-L-Lys-D-Ala-D-Ala + D-Ala) that maintains the concentration of the amide substrate at a constant level. In the presence of an amino acceptor X-NH2 (Gly-Gly or Gly-L-Ala) related to the Streptomyces peptidoglycan, both amide and ester carbonyl donors are processed without detectable accumulation of acyl-enzyme. Under proper conditions, the acceptor activity of water and, in the case of the amide substrate, the acceptor activity of the released D-alanine can be totally overcome so that the two substrates are quantitatively converted into transpeptidated product Ac2-L-Lys-D-Ala-NH-X (and hydrolysis is prevented). Experimental evidence suggests that the amino acceptor modifies both the binding of the carbonyl donor to the enzyme and the ensuing rate of enzyme acylation.
ISSN:0264-6021
1470-8728
1470-8728
DOI:10.1042/bj2350167