Purification and properties of a peptidase acting on a synthetic collagenase substrate from experimental granuloma tissue in the rat

Abstract

An enzyme which acts on a synthetic collagenase substrate, 4-phenylazobenzyl-oxycarbonyl-l-Pro-l-Leu-Gly-l-Pro-d-Arg (Pz-peptide) has been purified 250-fold from soluble extracts of experimental granuloma tissue of the rat and its properties studied. It is optimally active around pH 7.2. Its apparent Km value for Pz-peptide is 0.01 mM and V is 100 nmoles/mg protein per min. It is reversibly inhibited by p-hydroxymercuribenzoate (PHMB) and HgCl2, whereas iodoacetamide does not affect the enzyme activity. Heavy metals like Cu2+, Cd2+, Ag+, Ni2+ and Zn2+ completely inhibit the enzyme activity while the inhibition by Co2+ was only partial. Fe2+, Ba2+, Mn2+, Pb2+ and Ca2+ did not exert any affect on the activity. Chelating agents like EDTA, sodium diethyl dithiocarbamate and α,α′-dipyridyl do not affect the enzyme activity. Approximate molecular weight of the purified enzyme was estimated to be 56 000. © 1972.