ELECTROCHEMICAL INVESTIGATION OF ENZYME CATALYZED-HYDROLYSIS AND SYNTHESIS OF PEPTIDES USING PEPTIDYL-4-NITROANILIDES AS SUBSTRATES

The hydrolysis and synthesis of peptide catalysed by the serine protease dipeptidylpeptidase IV (E.C. 3.4.14.5) have been examined by differential pulse polarography (DPP) at the dropping mercury electrode. Gly-Pro-4-nitroanilide was used as the substrate. Both the latter and its hydrolysis product 4-nitroaniline are well detectable by DPP. The kinetic parameters of the hydrolysis have been determined in pure phosphate buffer and its mixtures with glycerol or DMSO. Further applications of DPP for measurements in coloured solutions and detection of the formation of the peptide bond are described. © 1990.