GENETIC VARIATION AFFECTING THE EXPRESSION OF CATALASE IN DROSOPHILA MELANOGASTER: CORRELATIONS WITH RATES OF ENZYME SYNTHESIS AND DEGRADATION

Glenn C. Bewley ¹ and Cathy C. Laurie-Ahlberg ¹

¹ Department of Genetics, North Carolina State University, Raleigh, North Carolina 27650

Both second and third chromosome substitution lines isolated from natural populations of Drosophila melanogaster affect the expression of catalase (EC 1.11.1.6) at both the larval and adult stages of development. In each case, the level of catalase activity is strongly related to the level of catalase-specific cross-reacting material. Turnover studies employing the catalase inhibitor 3-amino-1,2,4-triazole were conducted on a selected number of lines. Although the variation in steady state levels of catalase protein was highly significant among lines, variation in intracellular degradation rate was not. These results suggest that the different steady state levels observed among lines largely reflect different rates of catalase synthesis.