Activation of the latent human neutrophil gelatinase by urea

The mechanism of activation of the latent human neutrophil gelatinase by urea has been studied in greater detail. After dialysis of the latent gelatinase against increasing concentrations of urea a considerable increase of its activity was observed. Moreover, the results indicate a progressive conversion of the latent 94,000 Da gelatinase into a proteolytically active fragment of 80,000 Da, which was subsequently processed to a few species of lower molecular mass inactive against gelatin. This conversion was completely inhibited by EDTA, suggesting an autocatalytic reaction. The inhibition was reversed by Zn2+ or Co2+. Thus, urea alters both the enzymatic and physical characteristics of the latent gelatinase which suggests that conformational changes may induce autoactivation of the latent enzyme.