Human neutrophil collagenase (HNC) has been purified from extracts of fresh and outdated buffy coats and from exudates of phorbol myristate acetate-stimulated neutrophils. The MMP-8 present in the starting material can either be latent or active, or have an app. relative molecular mass of 75-kDa and/or 58-kDa. The rather complex pattern of activation of the latent 58-kDa and 75-kDa species by trypsin, organomercurials and oxidants has been investigated. MMP-8 was shown to preferentially hydrolyze type I over type II, and type III collagens in solution and to be a glycoprotein that contains complex N-linked oligosaccharides leading to multiple forms of MMP-8 in SDS-PAGE. The action of endoglycosidase on the latent 58-kDa form produces 42/40-kDa species (Gao et al. 1992, Mallya et al. 1990). This indicates that MMP-8 is an N-linked, complex glycoprotein that appears to be glycosylated at multiple sites.
