CONDUCTIMETRIC ASSAY OF PYROGLUTAMYL PEPTIDASE ACTIVITY

A conductimetric method was applied to assay Streptococcus pyogenes py roglutamyl peptidase (E.C. 3.4.8.11) activity using pyroglutamylalanin e or pyroglutamyltyrosine. A spectrophotometric comparison using pyrog lutamyl-beta-naphthylamide indicated that the sensitivity was much inc reased when using conductimetry. The use of a C-protected dipeptide su ch as pyroglutamylalanineamide also increased the sensitivity. Kinetic parameters have been measured for both dipeptides, with K-M values of 0.34 mM and 0.47 mM, respectively, for the alanine and tyrosine deriv atives.