Bhat M K, Kasturi S, Gowda T V
Department of Studies in Biochemistry, University of Mysore, India.
Toxicon. 1991;29(1):97-105. doi: 10.1016/0041-0101(91)90042-p.
Though venom phospholipases induce various pharmacological effects their mechanism of action is in some cases unclear. There may be separate pharmacological sites on the venom phospholipase molecule. In order to understand the structure-function relationships among venom phospholipases, studies on interaction of venom phospholipases with its antibodies and various alkaloids were carried out. The alkaloids aristolochic acid, ajmaline and reserpine were incapable of inhibiting the phospholipase A2 activity of NN-XIII-PLA2 but inhibited its edema inducing potency and partially inhibited the symptoms of neurotoxicity. The direct and indirect hemolytic activity remain unaffected. Polyclonal antibodies (anti PL-V Ig) to a neurotoxic PLA2 VRV PL-V neutralized the neurotoxic symptoms and lethality of VRV PL-V without affecting its in vitro phospholipase A2 activity when egg PC was used as the substrate. However, they inhibited the catalytic activity of VRV PL-V when synaptosomes were used as the substrate. Our results indicate the presence of multiple pharmacologically active sites apart from catalytic site.
尽管毒液磷脂酶会引发多种药理作用，但其在某些情况下的作用机制尚不清楚。毒液磷脂酶分子上可能存在不同的药理作用位点。为了了解毒液磷脂酶之间的结构-功能关系，开展了关于毒液磷脂酶与其抗体及各种生物碱相互作用的研究。马兜铃酸、阿吗灵和利血平这几种生物碱无法抑制NN-XIII-PLA2的磷脂酶A2活性，但能抑制其致水肿能力，并部分抑制神经毒性症状。直接和间接溶血活性不受影响。针对神经毒性磷脂酶A2 VRV PL-V的多克隆抗体（抗PL-V Ig）可中和VRV PL-V的神经毒性症状和致死性，在以卵PC为底物时不影响其体外磷脂酶A2活性。然而，当以突触体为底物时，它们会抑制VRV PL-V的催化活性。我们的结果表明，除催化位点外还存在多个药理活性位点。
