[Lipoamide dehydrogenase, citrate synthase, and beta-hydroxyacyl-CoA-dehydrogenase in skeletal muscles. X. The influence of frozen storage of bovine and porcine muscle on activity and subcellular distribution].

The influence of storage of bovine and porcine muscle at -20 degrees C for 12 months and of thawing on the total extractable activity and subcellular distribution (activities in the supernatant of a phosphate buffer extract and in the press juice of the thawed tissue) of the mitochondrial enzymes lipoamide dehydrogenase (LIPDH), citrate synthase (CS) and beta-hydroxyacyl-CoA-dehydrogenase (HADH) was studied. The total activity of LIPDH decreased during frozen storage whereas the activities of CS and HADH did not change appreciably. From the increase of CS and HADH activities in the muscle press juice it was concluded that--additionally to the effect of freezing and thawing itself--frozen storage results in further damage to the inner membrane of muscle mitochondria, which may be recognized from the increased release of membrane-bound enzymes. In this respect porcine muscle mitochondria seem to be more sensitive than bovine muscle mitochondria.