The Role of Esterases in the Pathogenesis of Disease and their Use as Diagnostic Tools

Abstract

The present classification of carboxylesterases by the latest Enzyme Commision Committee on Enzyme Nomenclature is neither unambigous nor satisfying. As pointed out by E. Reiner this becomes particularly evident within the two groups of enzymes reacting with organophosporous compounds, i.e. phosphotriester hydrolases (EC 3.1.8) and the “true” carboxylesterases like EC 3.1.1.1 or cholinesterase (3.1.1.8). Organophosphates are substrates of the former group and -formally- also of the latter one, the difference being only the incapability of the acyl residue to leave the active site in the case of carboxylesterases and therefore act as suicide substrates. The substrate specificity of the phosphoric triester hydrolases is still under discussion, particularly with regard to their reaction with carboxylesters. In this context it should be recalled that the phenyl acetate hydrolysing activity of human serum has not yet been separated from the paraoxon hydrolysing activity in a preparative manner.