Haemoprotein formation in yeast. III. The role of carbon catabolite repression in the regulation of catalase A and T formation.

Catalase A and T activities were investigated in two standard strains and three catalase regulatory cgr mutants of yeast in respiratory competent and incompetent states, which were under various degrees of glucose repression. The formation of catalase A was very sensitive to glucose repression and was characterized by a long delay in derepression. Deprivation of the energy source in respiratory incompetent cells prevented the derepression of catalase A. The lack of catalase A in respiratory imcompetent cells can be overcome by growing the cells in raffinose or by the prolongation of the fermentative phase of derepression. Catalase T is under control of different regulatory systems probably common with some other haemoproteins.