"However, the enzyme is a metalloproteinase since it is inhibited by EDTA, o-phenanthroline and tetraethylenepentamine (a specific zinc chelator). Metal analysis revealed 1 mol of zinc/mol of protein."

"Study of cleavage site preference of the fibrinolytic enzyme using the oxidized B chain of insulin revealed that specificity is similar to other snake venom metalloproteinases with cleavage primarily directed to an X-Leu bond."

"The enzyme exhibits direct fibrinolytic activity and does not activate plasminogen. In vitro studies revealed that fibrolase dissolves clots made either from purified fibrinogen or from whole blood."

"The enzyme, fibrolase, has a molecular weight of 23,000-24,000 and an isoelectric point of pH 6.8."

"It is composed of approximately 200 amino acids, possesses a blocked NH2-terminus and contains little or no carbohydrate."

"Interestingly, unlike some other venom fibrinolytic metalloproteinases, fibrolase exhibits little if any hemorrhagic activity."

"The enzyme shows no activity against a series of chromogenic p-nitroanilide substrates and is not inhibited by diisopropylfluorophosphate, soybean trypsin inhibitor, Trasylol, or p-chloromercuribenzoate. However, the enzyme is a metalloproteinase since it is inhibited by EDTA, o-phenanthroline and tetraethylenepentamine (a specific zinc chelator)."

"This is the first report of the sequence of a direct-acting, nonhemorrhagic fibrinolytic enzyme found in snake venom."

"Fibrolase is composed of 203 residues in a single polypeptide chain with a molecular weight of 22,891, as determined by the sequence."

"The amino-terminus is blocked by a cyclized glutamine (pyroglutamic acid) residue, and the sequence of this region of the molecule was determined by mass spectrometry."

"Its sequence is homologous to the sequence of the hemorrhagic toxin Ht-d of Crotalus atrox venom and with the sequences of two metalloproteinases from Trimeresurus flavoviridis venom."

"All six cysteine residues in fibrolase are involved in disulfide bonds. A disulfide bond between cysteine-118 and cysteine-198 has been established and bonds between cysteines-158/165 and between cysteines-160/192 are inferred from the homology to Ht-d."

"Secondary structure prediction reveals a very low percentage of alpha-helix (4%), but much greater beta-structure (39.5%)."

"Analysis of the sequence reveals the absence of asparagine-linked glycosylation sites defined by the consensus sequence: asparagine-X-serine/threonine."

"Microheterogeneity in the sequence was found at both the amino-terminus and at residues 189 and 192."