Partial primary structure of a fibrinogenase from the venom of the snake Lachesis stenophrys

The partial primary structure of an M-r 24 000 non-haemorrhagic metalloprot einase isolated from the venom of the snake Lachesis stenophrys has been de termined. The native proteinase was resistant to Edman degradation exhibiti ng the N-terminal blockade. The pyridylethylated or native proteinase was c hemically and enzymatically fragmented and the obtained peptides were separ ated by gel or reversed-phase chromatography, and sequenced. The metallopro teinase from Lachesis stenophrys contains a putative zinc-chelating sequenc e HELGHNLGMKH, characteristic for the reprolysin family of zinc-metalloprot einases. It contains six cysteine residues in the standard positions for th is group of proteins suggesting the same disulfide bonding. Interestingly, it has almost identical sequence as the metalloproteinase from Lachesis mut a muta, LHF-II, which is, however, haemorrhagic. The main structural differ ences between the two molecules were found in their N-terminal parts and in grycosylation. As the substrate-binding regions of both proteinases are pr actically identical, we suggest that the absence of haemorrhagicity in Lach esis stenophrys enzyme is due to its lower affinity for the matrix proteins and not due to different substrate specificity. (C) 1999 Elsevier Science B.V. All rights reserved.