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The other type of beta-lactamase is of the metallo type ("type B"). Metallo-beta-lactamases (MBLs) need metal ion(s) (1 or 2 Zn 2+ ions [2]) on their active site for their catalytic activities. [3] The structure of the New Delhi metallo-beta-lactamase 1 is given by 6C89. It resembles a RNase Z, from which it is thought to have evolved.
This resistance mechanism underscores the importance of the structural integrity of the β-lactam ring for the antibiotic's function. [24] The color change from colorless or light yellow to amber or even red in an aqueous solution of a β-lactam antibiotic can denote β-lactamase hydrolysis of amide bonds in the β-lactam ring.
This is a list of common β-lactam antibiotics—both administered drugs and those not in clinical use—organized by structural class. Antibiotics are listed alphabetically within their class or subclass by their nonproprietary name. If an antibiotic is a combination drug, both ingredients will be listed.
A lactam is a cyclic amide, and beta-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl. The simplest β-lactam possible is 2-azetidinone. β-lactams are significant structural units of medicines as manifested in many β-lactam antibiotics. [2]
Skeletal formulae of the basic structures of penicillin (1) and cephalosporin (2) antibiotics, highlighting the beta-lactam ring (red). Created using ACD/ChemSketch 10.0 and Inkscape . Legend
There are many beta lactamases which vary in substrate specificity and host range. [21] [22] The enzymes active site is easily regenerated hydrolytically so it is re-usable many times, in that way can a comparatively small amount of beta-lactamases destroy a large amount of drug. Gram-positive bacteria, such as a staphylococci, have a high ...
Currently available beta-lactamase inhibitors are effective against Ambler Class A beta-lactamases (tazobactam, clavulanate, and sulbactam) or against Ambler Class A, C and some Class D beta-lactamases (avibactam). Like beta-lactam antibiotics, they are processed by beta-lactamases to form an initial covalent intermediate.
Piperacillin is a broad-spectrum β-lactam antibiotic of the ureidopenicillin class. [1] The chemical structure of piperacillin and other ureidopenicillins incorporates a polar side chain that enhances penetration into Gram-negative bacteria and reduces susceptibility to cleavage by Gram-negative beta lactamase enzymes.