Y. Xu et al., RELATIVE SPECIFICITIES OF A SERIES OF BETA-LACTAM-RECOGNIZING ENZYMESTOWARDS THE SIDE-CHAINS OF PENICILLINS AND OF ACYCLIC THIOLDEPSIPEPTIDES, Biochemical journal, 302, 1994, pp. 851-856
In an attempt to understand more: of the subtle differences between ba
cterial beta-lactamases and DD-peptidases. comparisons have been made
between the specificities of these enzymes towards the phenylacetyl si
de chain, generally thought to be favoured by beta-lactamases, and the
NN'-diacetyl-L-lysyl side chain, widely employed in low-molecular-mas
s substrates of DD-peptidases. These comparisons were carried out with
both a penicillin and an acyclic thioldepsipeptide reaction nucleus a
nd employing a range of both beta-lactamases and DD-peptidases. Rather
contrary to general expectations, a general preference for reaction o
f both groups of enzymes with penicillins rather than thioldepsipeptid
es was observed and for the phenylacetyl rather than the NN'diacetyl-L
-lysyl side chain. Quantitative comparisons suggested that the side ch
ains of penicillins may be bound in relatively similar sites in all of
the enzymes whereas the side chains of thioldepsipeptides are more he
terogeneously bound, both with respect to each other and to the compar
able side chains of penicillins.