Alcohol dehydrogenase of Drosophila melanogaster: metabolic differences mediated through cryptic allozymes

Acetone formation from propan-2-ol, a saturated secondary alcohol, has been analysed in flies of three different Adh -gentypes of D. melanogaster . The in vivo oxidation of propan-2-ol was mainly mediated through ADH activity. It could be demonstrated that flies homozygous for the Adh 71k allele produced more acetone than flies homozygous for Adh F . This difference in metabolic flux mediated through the cryptic allozymes under non-saturated ADH-substrate conditions seems to be based on their different kinetic properties in vivo . Product inhibition of ADH monitored by means of ADH-isozymes conversion as observed after electrophoresis was similar for both cryptic allozymes. ADH-71k and ADH-F showed immunological identity, and the in vivo protein levels of ADH-71k were 25–30 per cent higher than ADH-F. The population-genetic implications of our findings have been evaluated.