頁籤選單縮合
題 名 | Phospholipases A[feaf]of Asian Snake Venoms |
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作 者 | Tsai,Inn-ho; | 書刊名 | 中央研究院生物化學研究所論文集 |
卷 期 | 23 1997[民86.] |
頁 次 | 頁247-281 |
分類號 | 361.4 |
關鍵詞 | |
語 文 | 英文(English) |
英文摘要 | This review up-dated the structural and functional information of various phospholipase A□ (PLA□) ISOFORMS PURIFIED FROM Asian snake venoms. A phylogenic tree of group I PLA□s was constructed herein based on many recently resolved amino acid sequences of the venom enzymes. It was found that PLA□s of Asian elapid venoms are structurally different from those of seasnake/Australian elapid venoms, and are usually associated with cardiovascular effect, although exceptions such as β-bungarotoxins do exit. Two types of venom PLA□s appear to be present in the venom of Asiatic viperinae such as Daboia and Echis, one has a N-terminal residue Asn and the other has the residue Ser. In the venom of Asiatic crotalinae, up to four subgroups of PLA□ isoforms are present and each of them is characterized by a distinct substitution at residue 6 (Glu, Asn or Arg) or residue 49 (Asp or Lys) in their sequences. The venom PLA□s in each of the subgroup show more or less functional similarity specific for the subgroup: the Glu6-PLA□s are usually antiplatelet, the Asn6-PLA□s are enurotoxic and/or myotoxic and many Arg6-PLA□s are anticoagulating, while the Lys49-PLA□S are myotoxic and edema-inducing. Mechanisms for the pharmacological actions of venom PLA□s have been discussed, including neurotoxicity, myotoxicity, antiplatelet activity, anticoagulating activity, heparin-binding, protein-acylation and deacylation. Conclusions derived from many recent studies on pancreatic PLA□by method of protein engineering render valuable information about the structure-activity relationship of the secretory PLA□ superfamily. Site-directed-mutagenesis methods coupled with relevant and dissecting functional assays are essential for understanding the structure-activity relationship of snake venom PLA□s with special function or toxicity. |
本系統中英文摘要資訊取自各篇刊載內容。