Influence of age on mitochondrial enzyme levels in Drosophila

The specific activity and the activity per fly of four mitochondrial enzymes did not change with ageing in male Drosophila melanogaster (Oregon R). The enzymes assayed were rotenone-insensitive NADH-cytochrome c reductase, adenylate kinase, succinate cytochrome c reductase, and malate dehydrogenase, located in the outer membrane, inner membrane space, inner membrane and matrix, respectively. The specific activity of malate dehydrogenase showed no significant change for young and old head, thorax and abdomen. We conclude that there is no specific site for ageing damage in the mitochondrion, when the enzyme activities in this study are used as an indicator. It should be noted, however, that these enzymes represent only a small percentage of the total enzymes present in mitochondria.