Abstract
Eight esters (acetates and butyrates) of four phenolic naphthylazo compounds with sulfonic acid group (s) were synthesized and assessed as water-soluble chromogenic substrates for the assay of esterases. The absorption maxima of azo compounds produced enzymatically from these esters occur at wavelengths about 100 nm longer than those of the esters and their molar absorptivities are, higher than those of the esters. Investigations on the substrate specificities of these esters revealed, that all the esters are hydrolyzed by carboxyl esterase- and aryl esterase-mediated reactions, and butyrates of m-(4-hydroxy-1-naphthylazo) benzenesulfonic acid and Azorubin should be particularly useful as substrates for cholinesterase and aryl esterase, respectively.
