RTEM p-lactamase

Folding Equilibrium Studies. E. coli RTEM p-lactamase is a monomeric protein. Its amino acid sequence has been determined (79). It has one disulfide bond between the residues Cys S and Cys. The presence of four tyrosines and four tryptophans allows the use of spectroscopic method for the conformational characterization of the enzyme. In this study, the effect of denaturants on the unfolding of p-lactamase was determined from activity measurements, difference spectroscopy and fluorescence intensity measurements. 

Over 80 different (3-lactamases are now known. One classification is a system that divides the enzymes into three classes A, B, and C. Classes A and C are active-site serine enzymes. The serine residue in class A enzymes is at position 70. This class contains four major (3-lactamases 749/C (from B. licheniformis), PCI (from S. aureus), 569/H P-lactamase I (from B. cereus), and PBR322 and RTEM (from E. coli). As with other serine-type hydrolytic enzymes (acetylcholinesterase, trypsin), the mechanism of action requires initial formation of an acylated enzyme, in this case acylation of ser-70 followed by hydrolysis of the derivative to regenerate the enzyme ... 

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