Detection of Microsomal Phospholipase Activity in Myotomal Tissue of Atlantic Cod ( Gadus morhua )

Incubation of microsomes prepared from myotomal tissue of Atlantic cod yielded detectable phospholipase activity following incubation with 1,2‐dipalmitoyl‐9,10‐[ 3 H]‐phosphatidylcholine over a period of 24 hr. No significant incidence of nonenzymatic hydrolysis was found to accompany the determined phospholipase activity. Phospholipid hydrolysis increased linearly in the presence of increasing levels of microsomal protein (0–4 mg). Optimal phospholipase enzyme activity was determined following incubation at 20°C and maximal activity was determined in the presence of 0.1 nmole unlabelled lecithin substrate. The myotomal microsome preparation of Atlantic cod proved to be a suitable model for direct evaluation of phospholipase and perhaps might be useful in evaluation of frozen storage impact on the resultant integrity of the enzyme system.