ISSN:
1573-3904
Keywords:
dd-Peptidases
;
β-Lactamases
;
Thiolesters
;
Stereospecificity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary With peptide substrates, the penicillin-sensitive dd-peptidases exhibit a strict specificity for d-Ala-d-Xaa C-termini. Only glycine is tolerated as the C-terminal residue, but with a significantly decreased activity. These enzymes also hydrolyse various ester and thiolester analogues of their natural substrates. Some of the thiolesters whose C-terminal leaving group exhibited an l stereochemistry were significantly hydrolysed by some of the studied enzymes, particularly by the Actinomadura R39 dd-peptidase. By contrast, the strict specificity for a d residue in the penultimate position was fully retained. The same esters and thiolesters also behaved as substrates for β-lactamases. In this case, thiolesters exhibiting l stereochemistry in the C-terminal position could also be hydrolysed, mainly by the class C and class D enzymes. But, more surprisingly, the class C Enterobacter cloacae P99 β-lactamase also hydrolysed thiolesters containing an l residue in the penultimate position, sometimes more efficiently than the d isomer.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00119156
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