市販生鮮カツオ肉における lysophosphatidylcholine 及び lysophosphatidylethanolamine の蓄積について

抄録

Phosholipids of the muscle of fresh skipiack Euthynnus pelamis were analyzed by HPLC, GLC, and TLC. The contents of lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) in skipjack muscle were extremely high, though earlier workers had reported that the contents of LPC adn LPE produced enzymatically in the fish muscle were considerably low and did not increase during frozen storage. The accumulation of LPC and LPE in the skipjack muscle might be elucidated by either saying that the activity of phospholipase A₂ is higher than that of lysophospholipase or that the lower pH of skipjack muscle influences the activity of lysophospholipase; the optimum pH of lysophospholipase in fish muscle is known ot be around 7.6.
The fatty acid compositions of phosphatidylcholine (PC), LPC, and free fatty acid were analyzed. Percentage of C_22:6 was considerably high in the PC, while extremely low in the LPC. These results seem to indicate either that most of the PC having C_22:6 located on the α-position of glycerol is not attacked by the action of phospholipase A₂ or that the LPC having C_22:6, if produced from PC by the action of phospholipase A₂, is attacked preferentially by the action of lysophospholipase to librate C_22:6.
The possible fatty acid combinations of the PC remaining in hte skipjack muscle were also presented.