CHANGES IN ENZYME LEVELS DURING AGEING IN DROSOPHILA MELANOGASTER

The distribution of protein between the subcellular fractions of whole body homogenates of male Drosophila melanogaster was found to change with adult age. There is less protein in the "soluble" fraction (135 000 x g supernatant), "micro-somal" fraction (135 000 x g precipitate), and "mitochondrial" fraction (18 000 x g precipitate), and more protein in the "insoluble" fraction (5 000 x g precipitate) of old fly homogenates compared to the corresponding fractions of young fly homogenates. It was also shown that the whole body activities of several enzymes, namely trehalase, alpha-glycerolphosphate dehydrogenase, esterase and alcohol dehydrogenase, decrease as this insect ages, though to different extents. The total body activity of glutamic aspartic transaminase does not change significantly throughout adult life. The age-related changes observed are discussed collectively in relation to the current theories of ageing at the molecular level.