Abstract.
The catalytic action of serine peptidases depends on the interplay of a nucleophile, a general base and an acid. In the classic trypsin and subtilisin families this catalytic triad is composed of serine, histidine and aspartic acid residues and exhibits similar spatial arrangements, but the order of the residues in the amino acid sequence is different. By now several new families have been discovered, in which the nucleophile-base-acid pattern is generally conserved, but the individual components can vary. The variations illustrate how different groups and different protein structures achieve the same reaction.
Key words. Mechanisms of peptidase action, β-lactamase, cytomegalovirus, Ntp-hydrolyses, oxyanion binding site
Footnotes
Received 13 April 2005; received after revision 18 May 2005; accepted 24 May 2005