Intestinal absorption of several .BETA.-lactam antibiotics. III. Competitive inhibition behavior among zwitterionic .BETA.-lactam antibiotics in the rat intestinal absorption.

1982 ◽  
Vol 5 (8) ◽  
pp. 555-563 ◽  
Author(s):  
KATSUMI MIYAZAKI ◽  
KYOKO OHTANI ◽  
KAZUTOSHI UMENIWA ◽  
TAKAICHI ARITA
Keyword(s):  
Intestinal Absorption ◽  
Competitive Inhibition ◽  
Beta Lactam ◽  
Beta Lactam Antibiotics

scholarly journals Substrate-induced inactivation of the OXA2 β-lactamase

1993 ◽  
Vol 295 (3) ◽  
pp. 871-878 ◽  
Author(s):  
P Ledent ◽  
J M Frère
Keyword(s):  
Competitive Inhibition ◽  
Hydrolysis Product ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Hydrolysis Time ◽  
Beta Lactam Antibiotics ◽  
Class D ◽  
Time Courses ◽  
Burst Kinetics ◽  
Hydrolysis Of

The hydrolysis time courses of 22 beta-lactam antibiotics by the class D OXA2 beta-lactamase were studied. Among these, only three appeared to correspond to the integrated Henri-Michaelis equation. ‘Burst’ kinetics, implying branched pathways, were observed with most penicillins, cephalosporins and with flomoxef and imipenem. Kinetic parameters characteristic of the different phases of the hydrolysis were determined for some substrates. Mechanisms generally accepted to explain such reversible partial inactivations involving branches at either the free enzyme or the acyl-enzyme were inadequate to explain the enzyme behaviour. The hydrolysis of imipenem was characterized by the occurrence of two ‘bursts’, and that of nitrocefin by a partial substrate-induced inactivation complicated by a competitive inhibition by the hydrolysis product.

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