The development of tyrosinase and cytochrome oxidase activity in mutants of Glomerella cingulata

Abstract

Cytochrome oxidase activity in the standard type and in four mutants of Glomerella cingulata has been shown to be constant throughout the mycelial development. This enzyme is concentrated on mitochondria-like particles which are extractable in hypertonic solutions of disaccharides. On the other hand, tyrosinase activity is concentrated in the supernatant and changes markedly during the development of the organism. This enzyme is present in the standard type and in two of the mutants, while the other two mutants have only minimal amounts. In the mycelia having such activity, tyrosinase increases precipitously, after the peak of growth has been reached, and then declines almost immediately, although small amounts of tyrosinase remain in the mycelium for as long as it is possible to obtain extracts. The evidence suggests that tyrosinase cannot function as the terminal oxidase during growth, although cytochrome oxidase can function in this way.