Babu A S, Gowda T V
Department of Studies in Biochemistry, University of Mysore, Manasagangotri, India.
Toxicon. 1991;29(10):1251-62. doi: 10.1016/0041-0101(91)90197-y.
The effects of chemical modification with 4-NN-dimethyl amino azo benzene-4'-isothiocyanate on various biological activities of phospholipases A2, NN-XIII-PLA2 from Naja naja naja and VRV-PL-VIIIa from Vipera russelli snake venoms were investigated. Modification of the enzymes resulted in significant reduction of lethal, hemolytic, anticoagulant and enzymatic activities. The Km value of the modified enzymes was increased. The modified enzymes failed to induce edema in the foot pads of mice and were non-lethal up to 16 mg/kg body weight. However, considerable myotoxicity was retained, suggesting that the toxins have multiple sites for biological activities. The aggregated form obtained from modified NN-XIII-PLA2 exhibited decreased enzymatic activity and increased toxicity compared to the modified monomer. This aggregated form did not show pyrophosphatase/phosphomonoesterase activity in contrast to the aggregated form obtained from the native NN-XIII-PLA2 molecule.
研究了用4-二甲基氨基偶氮苯-4'-异硫氰酸酯进行化学修饰对眼镜蛇毒中的磷脂酶A2、Naja naja naja的NN-XIII-PLA2和蝰蛇毒中的VRV-PL-VIIIa的各种生物学活性的影响。酶的修饰导致致死、溶血、抗凝和酶活性显著降低。修饰酶的Km值增加。修饰酶未能在小鼠脚垫中诱导水肿，且在高达16 mg/kg体重时无致死性。然而，相当程度的肌毒性得以保留，这表明毒素具有多个生物活性位点。与修饰单体相比，由修饰的NN-XIII-PLA2获得的聚集形式表现出酶活性降低和毒性增加。与从天然NN-XIII-PLA2分子获得的聚集形式相反，这种聚集形式未显示焦磷酸酶/磷酸单酯酶活性。
