The complete amino acid sequence of fibrolase, a fibrinolytic enzyme from southern copperhead (Agkistrodon contortrix contortrix) venom, has been determined. This is the first report of the sequence of a direct-acting, nonhemorrhagic fibrinolytic enzyme found in snake venom. The majority of the sequence was established by automated Edman degradation of overlapping peptides generated by a variety of selective cleavage procedures. 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. Fibrolase is composed of 203 residues in a single polypeptide chain with a molecular weight of 22,891, as determined by the sequence. 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 Trimeresurusflavoviridis venom. Microheterogeneity in the sequence was found at both the amino-terminus and at residues 189 and 192. 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 a-helix (4"70), but much greater 0-structure (39.5%). Analysis of the sequence reveals the absence of asparagine-linked glycosylation sites defined by the consensus sequence: asparagine-X-serine/threonine. Keywords: amino acid sequence; secondary structure; snake venom fibrolase Fibrinolytic activity has been found in the venom of snakes from the families Crotalidae, Viperidae, and Elapidae, with venom from members of the Crotalidae having the highest levels of fibrinolytic activity (for a recent review, see Markland, 1988). Fibrolase is a direct-acting fibrinolytic enzyme from southern copperhead (Agkistrodon contortrix contortrix) venom that does not require bloodborne cofactors for activity (Guan et al., 1991). As previously described (Markland, 1983;Markland et al., 1988; Reprint requests to: Anne Randolph, Chiron Research Laboratories, Retzios & Markland, 1988), the enzyme is a nonhemorrhagic, zinc metalloproteinase which cleaves primarily the a-chain of human fibrinogen and fibrin. Specific cleavage sites have been determined for several venom metalloproteinases using natural or synthetic substrates (Tu et al., 1981;Hagihara et al., 1985;Fox et al., 1986;Mori et al., 1987).

Pracparatum mungo is a typical functional food for Chinese. First, Green bean was manufactured through natural fermentation, then soaking in aqueous Chinese herbal medicine mixture, finally dry by room temperature process to become the refining of natural functional food as Pracparatum mungo. Pracparatum mungo used to use as a traditional medicinal food for liver protection and detoxification in China. The aim of this study was to investigate the histological and biochemical changes in liver of balb/c mice after oral administration Pracparatum mungo. For this purpose, 30male balb/c mice were divided into three groups. Group A only received vehicle and normal chow diet. Group B, C received 25mg/day and 50mg/day Pracparatum mungo with normal diet, respectively. Animal were scarified after 4 weeks, liver tissue and blood sample were obtained. The liver tissue specimens were examined under microscope. The level of ALT, AST, SOD, Caltase, GPX, and GST were determined from serum. The levels of catalase, SOD, GPx, GST activity were significantly increase in Group C. Light microscopic examination of liver specimens reveled normal in all groups. In conclusion, oral administration Pracparatum mungo may enhance liver protection ability to against stress cause liver damage.