Macrophage metalloelastase (MMP-12) is implicated in the pathology of many
diseases such as emphysema, aortic lesions and cancer. Recently, MMP-12 was
cloned and purified from mouse and human macrophages. We report here the e
xpression of the full-length and catalytic domain of rat MMP-12 in Escheric
hia coli and characterization of the purified enzyme. Inclusion bodies of e
xpressed rat MMP-12 catalytic domain were denatured and refolded using a ne
w method, and then affinity purified to near homogeneity with zinc chelatin
g Sepharose, The purified rat MMP-18 catalytic domain was highly active in
digesting substrates, having a K-m of 12 muM and optimal pH of 7.5-8.5. Dur
ing investigation of natural substrate specificity, we found that rat MMP 1
2 catalytic domain was able to completely degrade collagen-V, partially deg
rade collagen-I, but it was unable to digest collagen-IV. The enzyme could
also degrade osteonectin, vitronectin, and fibronectin, but not laminin and
albumin. The catalytic properties and natural substrate specificity of rat
MMP-12 catalytic domain differed from those of human MMP-12 catalytic doma
in, (C) 2001 Academic Press.