Biochemical properties of metalloproteinases from the hemolymph of the mussel Mytilus galloprovincialis Lam.

The expression of matrix metalloproteinases (MMP) with gelatinase activity was found in the whole hemolymph of the marine mussel Mytilus galloprovinci alis Lam. Cleavage activity was specific for gelatin; very little activity towards human type-IV collagen, and no activity for cold fish gelatin, case in or bovine serum albumin were detected. EDTA and 1,10-phenanthroline were inhibitory, suggesting that mussel MMPs require divalent cations for their proteolytic activity; in fact, the presence of exogenously added divalent ions significantly protected the MMPs from inhibition. No inhibition was de tected with serine or cysteine proteinase inhibitors. The specific vertebra te inhibitors as well as the classical vertebrate activator of MMPs were wi thout effect, whereas sulphydryl reducing agents had a strong inhibitory ef fect. Mussel MMPs showed an exponential curve of thermal-dependent decay th at was not protected by the presence of metal ions. Overall the results ind icate both similarities and differences between invertebrate and vertebrate gelatinases, providing information for understanding the biological role o f these ancient proteinases. (C) 2001 Elsevier Science Inc. All rights rese rved.