Rakhimov M M, Akhmedzhanov R, Tachmukhamedov B A
Biokhimiia. 1979 Jan;44(1):33-9.
The rates of the reaction products formation under simultaneous phospholipase D effect on phosphatidyl ethanolamine and phosphatidyl choline were studied. The hydrolysis of cephalin, unlike the phospholipase D effect on lecithin, does not require Ca2+ ions. Ca2+ does not affect the enzymatic degradation of lecithin and inhibits the reaction with cephalin in "inorganized" phospholipid emulsions. The hydrolysis of micellar phospholipids by phospholipase D (in the presence of the anionic detergent sodium dodecyl sulfate) is accelerated by Ca2+ ions for both substrates. The apparent Km value is equal to 1.5 mM and does not depend on the phospholipid type. In contrast, the value of kcat for lecithin is twice as high as that for cephalin. It was demonstrated that the phase state of the phospholipids and the chemical nature of the alcohol residue in the phospholipid molecule are essential for the substrate specificity of phospholipase D.
研究了磷脂酶D同时作用于磷脂酰乙醇胺和磷脂酰胆碱时反应产物的生成速率。与磷脂酶D对卵磷脂的作用不同，脑磷脂的水解不需要Ca2+离子。Ca2+不影响卵磷脂的酶促降解，且在“无组织”的磷脂乳液中抑制与脑磷脂的反应。对于两种底物，在磷脂酶D（存在阴离子去污剂十二烷基硫酸钠）作用下，胶束磷脂的水解都因Ca2+离子而加速。表观Km值等于1.5 mM，且不依赖于磷脂类型。相比之下，卵磷脂的kcat值是脑磷脂的两倍。结果表明，磷脂的相态和磷脂分子中醇残基的化学性质对磷脂酶D的底物特异性至关重要。
