Raykova D, Blagoev B
Toxicon. 1986;24(8):791-7. doi: 10.1016/0041-0101(86)90104-2.
In order to find out the aggregation state of the substrate, preferred by bee venom phospholipase A2 (EC 3.1.1.4), its action on short-chain phosphatidylcholines with two identical (C6-C10) fatty acids has been tested. The rate of hydrolysis as a function of acyl chain length showed a maximum at dioctanoylphosphatidylcholine. The effects of alcohols, NaCl and Triton X-100, which affect the aggregation state of phospholipids in water, were also studied. The addition of n-alcohol led to a significant inhibition of the hydrolysis of the substrates present in micellar form and activated the hydrolysis of substrates which form liposomes. The inhibitory effect increased with increasing length of the aliphatic carbon chain of the alcohol. Triton X-100 at low Triton/phospholipid molar ratios enhanced enzyme activity. These results do not agree with the accepted idea that bee venom phospholipase A2 hydrolyzes short-chain lecithins in their molecularly dispersed form and that micelles cannot act as substrates. The data indicate that short-chain lecithins in the aggregated state are hydrolyzed and that the requirements of bee venom phospholipase A2 for the aggregation state of the substrate are not strict.
为了弄清楚蜂毒磷脂酶A2（EC 3.1.1.4）所偏好的底物聚集状态，测试了其对含有两个相同（C6 - C10）脂肪酸的短链磷脂酰胆碱的作用。水解速率作为酰基链长度的函数，在二辛酰磷脂酰胆碱处出现最大值。还研究了影响水中磷脂聚集状态的醇、NaCl和吐温X - 100的作用。添加正醇导致对以胶束形式存在的底物的水解有显著抑制，并激活形成脂质体的底物的水解。抑制作用随醇的脂肪族碳链长度增加而增强。在低吐温/磷脂摩尔比下，吐温X - 100增强了酶活性。这些结果与公认的观点不一致，即蜂毒磷脂酶A2水解分子分散形式的短链卵磷脂，且胶束不能作为底物。数据表明聚集状态的短链卵磷脂会被水解，并且蜂毒磷脂酶A2对底物聚集状态的要求并不严格。
