Phospholipase A1 activity of crude enzyme extracted from the ovaries of skipjack tuna |
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| Authors: | Seiichi Hiratsuka Tomoko Kitagawa Kouta Yamagishi Shun Wada |
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| Affiliation: | (1) Shizuoka Prefectural Research Institute of Fishery, Yaizu, 425-0033 Shizuoka, Japan;(2) Maruhachi Muramatsu, Inc., Yaizu, 425-0025 Shizuoka, Japan;(3) Department of Marine Science, Tokai University, 424-8610 Shizuoka, Japan;(4) Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Minato, 108-8477 Tokyo, Japan |
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| Abstract: | The phospholipid class composition, fatty acid composition and phospholipase A1 (PLA1) activity from the ovaries of skipjack tuna were compared with those of six other species of marine fish. In the skipjack ovaries, the lysophosphatidylcholine (LPC) proportion for the phospholipid, the docosahexaenoic acid (DHA) percentage for the total fatty acids of the phospholipids and the PLA1 activity of the crude enzyme were the highest among those of the seven species. The optimum pH and temperature for the PLA1 activity of the crude enzyme from the skipjack ovaries were in the range of pH 6–7 and 20–30°C, respectively, and calcium ions were not required. As a substrate, phosphatidylcholine was more easily hydrolyzed than phosphatidylethanolamine by this enzyme, and the plasmalogen-type phospholipid was much lower than the acyl-type phospholipid. After a 6-h hydrolysis reaction of the purified phospholipid extracted from the mixed ovaries of skipjack and yellowfin tuna by this enzyme, the LPC ratio of the phospholipid increased from 20 to 72.6% and the percentage of DHA for the total fatty acids of the phospholipid also increased. Thus, skipjack ovaries might possibly be used as a source of PLA1. |
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| Keywords: | fatty acid lipid class lysophosphatidylcholine ovary phospholipase A1 skipjack |
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