雨傘節神經毒的生化研究

Abstract

台灣雨傘節(Bungarus multicinctus)蛇毒之β-神經毒蛋白（β-Bungarotoxin）經由CM-Sephadex C-25，Sephadex G-50提取精製完成。 利用CD技術來探討各種媒體對β-雨傘節神經毒的影響。發現自然分子的CD光譜表現典型的α結構，在低溶性溶劑如1,2-ethane-diol中，其立體結構與水溶液相似，但在6.0 M guanidine hydrochloride中，其規則的立體結構(ordered structure)變成不規則的結構(unordered structure)。 β-雨傘節蛇毒由兩個蛋白質分子鍵（A和B）以雙硫鍵連接而成，分子量22,000左右。其A分子和磷酯酸水解?的初級結構相似，比較各種磷酯酸水解?與β-雨傘節蛇毒α結構的穩定性，再利用CNBr修飾法由A蛋白質鍵打掉8個胺基酸，並測定其α結構的穩定性。比較修飾過後的蛇毒與自然蛇毒的毒性，可以得知A和B蛋白質分子鍵間有交互作用。

The snake venom of Bungarus multicntus was chromatographied by CM-Sephadex C-25 into 13 fraction. Fraction X was then isolated and purified by G-50 column into 2 fractions. Peak 1 was identified to be β-Bungarotoxin. This protein containst two polypeptide chains (A chain molecular weight 13,500, B chain molecular weight 7,500). Using the CD technique to study the median effect on β-Bungarotoxin, we found that the native spectra has double minima-at 222 nm and 209 nm which is Characteristic of α-helical structure. Determination of helix-coil transition of PLA, β-Bungarotoxin and CNBY-β-Bungarotoxin indicated that there is interaction between A- and B- polypeptide Chain.