Hirano K, Tanaka A, Yoshizumi K, Tanaka T, Satouchi K
Department of Food Science and Technology, Fukuyama University, Hiroshima.
J Biochem. 1997 Dec;122(6):1160-6. doi: 10.1093/oxfordjournals.jbchem.a021876.
The properties of phospholipase A1 (PLA1) obtained from the white muscle of bonito, Euthynnus pelamis (Linnaeus), were examined. The PLA1 activity had a pH optimum from 6.5 to 7.0 for phosphatidylcholine (PC), and calcium ion was not required. The optimum temperature was from 20 to 30 degrees C. When a fatty alcohol was used as an acceptor, a wax ester was produced by transferring a fatty acid at the sn-1 position of the donor's PC. The maximum production of lysophosphatidylcholine was shifted by 0.5 pH units to the acidic side and the pH optimum of wax ester synthesis was from 6.0 to 6.5. The synthesis was independent of calcium ion and Coenzyme A. The transacylation was also observed when 1-lyso-2-acyl-sn-glycero-3-phosphocholine was used as an acceptor. Fatty acid at the sn-1 position of the donor PC was transferred to the unoccupied hydroxy group of the acceptor at the sn-1 position. When 2,3-dipalmitoyl-sn-glycero-1-phosphocholine was used as the acyl donor, a similar amount of palmitic acid was transferred as in the case of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. However, 1-acyl-2-lyso-sn -glycero-3-phosphocholine, a positional isomer, was a poor acceptor. These results indicate that the transacylation by the PLA1 from bonito muscle is not stereospecific, but is position-specific both for the acyl donor and acceptor.
对从鲣鱼（Euthynnus pelamis，林奈）白肌中提取的磷脂酶A1（PLA1）的特性进行了研究。对于磷脂酰胆碱（PC），PLA1活性的最适pH值为6.5至7.0，且不需要钙离子。最适温度为20至30摄氏度。当使用脂肪醇作为受体时，通过转移供体PC的sn-1位上的脂肪酸可生成蜡酯。溶血磷脂酰胆碱的最大产量向酸性方向移动了0.5个pH单位，蜡酯合成的最适pH值为6.0至6.5。该合成过程与钙离子和辅酶A无关。当使用1-溶血-2-酰基-sn-甘油-3-磷酸胆碱作为受体时，也观察到了转酰基作用。供体PC的sn-1位上的脂肪酸转移到了受体sn-1位上未占据的羟基上。当使用2,3-二棕榈酰-sn-甘油-1-磷酸胆碱作为酰基供体时，转移的棕榈酸量与1,2-二棕榈酰-sn-甘油-3-磷酸胆碱的情况相似。然而，1-酰基-2-溶血-sn-甘油-3-磷酸胆碱，一种位置异构体，是一种较差的受体。这些结果表明，鲣鱼肌肉中的PLA1进行的转酰基作用不是立体特异性的，而是对酰基供体和受体都具有位置特异性。
