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Temperature‐dependent deacylation of molecular species of phosphatidylcholine by microsomal phospholipase A 2 of thermally acclimated rainbow trout, Salmo gairdneri 1
Author(s) -
Neas N. P.,
Hazel J. R.
Publication year - 1984
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02534453
Subject(s) - rainbow trout , phosphatidylcholine , salmo , microsome , trout , chemistry , enzyme , substrate (aquarium) , biochemistry , acclimatization , chromatography , phospholipid , biology , fish <actinopterygii> , membrane , fishery , ecology
Using the ratios of kinetic parameters, V/Km, the deacylation of different molecular species of 1‐palmitoyl,2‐acyl phosphatidylcholine via microsomal phospholipase A 2 (PLA 2 ) was studied in liver tissue of thermally acclimated rainbow trout ( Salmo gairdneri ). In general, PLA 2 from fish acclimated to cold temperatures showed an order of preference for the acyl moieties of 18∶1>18∶1>18∶2>18∶0. Trout acclimated to warm temperatures generally preferred 18∶0 PC, but the actual order of preference depended on the temperature of the assays and the presence of endogenous lipids in the enzyme preparation. At 5 C, the particulate (microsomal) enzyme preferred 18∶0>18∶2>18∶1, but a lipid‐free preparation of the enzyme preferred 18∶2>18∶0>18∶1. At 20 C, particulate enzyme preferred 18∶1>18∶0>18∶2 but purified enzyme preferred 18∶0>18∶2>18∶1. Thus, assay temperature and the presence of microsomal lipids had a greater effect on PLA 2 from fish acclimated to warm temperatures than fish acclimated to cold temperatures. The substrate preference of PLA 2 is discussed with reference to the previously observed changes in membrane fatty acid composition that occur with thermal acclimation in rainbow trout.