Properties of phenoloxidases generated from prophenoloxidase with 2-propanol and the natural activator in Drosophila melanogaster

Prophenoloxidases A(1) and A(3) in Drosophila melanogaster were activated w ith 2-propanol and a partially purified natural activator For prophenoloxid ase activation the optimum temperature was 30 degrees C and the optimum pH was 8. Both mono- and diphenoloxidase activities were found in A(1) and A(3 ) activated with 2-propanol, whereas only diphenoloxidase activity was dete cted in A(3) activated with a natural activator The kinetic properties, K-m and V-max, were not similar in those phenoloxidases activated with differe nt activating agents. The rate of inhibition of phenoloxidase by diethyldit hiocarbamate and phenylthiocarbamate depended on the concentration of 2-pro panol. Both compounds exhibited a noncompetitive pattern of inhibition.