Ž . Comparative Biochemistry and Physiology Part B 128 2001 507515 Biochemical properties of metalloproteinases from the hemolymph of the mussel Mytilus galloproincialis Lam. Ferdinando Mannello a, , Laura Canesi b , Giancarlo Gazzanelli a , Gabriella Gallo c a Istituto di Istologia ed Analisi di Laboratorio, Facolta di Scienze Matematiche, Fisiche e Naturali, Libera Uni ersita degli ` ` ( ) Studi, Via E. Zeppi, 61029 Urbino PU , Italy b Istituto di Scienze Fisiologiche, Facolta di Scienze Ambientali, Libera Uni ersita degli Studi, Loc. Crocicchia, ` ` ( ) 61029 Urbino PU , Italy c Dipartimento di Biologia Sperimentale Ambientale ed Applicata, Uni ersita di Genoa, Viale Benedetto XV, 16132, ` ( ) Genoa GE , Italy Received 29 July 2000; received in revised form 10 November 2000; accepted 4 December 2000 Abstract Ž . The expression of matrix metalloproteinases MMP with gelatinase activity was found in the whole hemolymph of the marine mussel Mytilus galloproincialis Lam. Cleavage activity was specific for gelatin; very little activity towards human type-IV collagen, and no activity for cold fish gelatin, casein 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 detected with serine or cysteine proteinase inhibitors. The specific vertebrate inhibitors as well as the classical vertebrate activator of MMPs were without effect, whereas sulphydryl reducing agents had a strong inhibitory effect. Mussel MMPs showed an exponential curve of thermal-dependent decay that was not protected by the presence of metal ions. Overall the results indicate both similarities and differences between invertebrate and vertebrate gelati- nases, providing information for understanding the biological role of these ancient proteinases. 2001 Elsevier Science Inc. All rights reserved. Keywords: Extracellular matrix; Metalloproteinase; Mussel; Hemocyte; Hemolymph; Gelatinase; Mytilus galloproincialis Lam.; Zymography Corresponding author. Tel.: 39-0722-320168; fax 39-0722-322370. Ž . E-mail address: mannello@uniurb.it F. Mannello . 1096-495901$ - see front matter 2001 Elsevier Science Inc. All rights reserved. Ž . PII: S 1 0 9 6 - 4 9 5 9 00 00352-3