EC 5.3.1.9 From Saccharomyces cerevisiae. Electrophoretically homogeneous (MW 62,400). Single major band on isoelectric focusing (pI 6.1); minor band pI 6.9. In 3.2M ammonium sulphate. Specific activity: ~ 650 U/mg of protein (25°C, pH 7.6) or ~ 850 U/mg of protein (40°C, pH 7.6). Contaminants: hexokinase < 0.01 %; glucose 6-phosphate dehydrogenase < 0.001 %; phosphomannose isomerase < 0.01 %; α-glucosidase < 0.0001 %; and ?-glucosidase; < 0.0001 %; NADH oxidase < 0.001 %. Stable at 4°C for > 4 years.