[Hexokinase and sucrose phosphorylase activity of cell-free preparations of haploid and diploid strains of Pullularia pullulans].

The autodiploid strain of Pullularia pullulans 1125(4)(13) that differs from the haploid strain 1125(4) in the rate of synthesis of the polysaccharide pullulan has a higher activity of hexokinase in cell-free preparations. A change in the activity of hexokinase in the diploid strain coincides in time with a change in the rate of the polysaccharide synthesis: the activity of hexokinase in cell-free preparations is highest when the rate of pullulan synthesis is maximal. In the haploid strain, the activity of hexokinase in preparations from the cultures grown for 24, 38 and 48 hours remains at the same level, and then decreases by the 72nd hour. The activity of sucrose phosphorylase in cell-free preparations of the haploid strain increases with aging of the culture; in preparations of the diploid strain, the activity decreases by the 38th hour and then increases like in the haploid strain. These data make it possible to suggest that the activity of hexokinase, rather than that of sucrose phosphorylase, influences the rate of pullulan synthesis.