Isolation of a regulatory mutant of fructose-1,6-diphosphatase in Saccharomyces carlsbergensis.

By selecting for growth on glycerol, but absence of growth on glucose, a mutant of Saccharomyces carlsbergensis was isolated which does not grow on glucose, fructose, mannose, or sucrose, which shows long-term adaptation to maltose, but which can grow normally on galactose, ethanol, or glycerol. In the mutant, fructose diphosphatase is not inactivated after the addition of glucose, fructose or mannose to the medium, resulting in the simultaneous presence of fructose diphosphatase and phosphofructokinase activity. Under these conditions, a cycle is probably catalyzed between fructose-6-phosphate and fructose-1,6-diphosphate, resulting in the net consumption of adenosine triphosphate and an immediate stop of protein synthesis.