EC 5.3.1.9 From Escherichia coli. Electrophoretically homogeneous (MW 62,600). Single major band on isoelectric focusing (pI 5.3); several minor bands pI 5.3-5.5. In 3.2M ammonium sulphate. Specific activity: ~ 700 U/mg of protein (25°C, pH 7.6) or ~ 1200 U/mg of protein (40°C, pH 7.6). Contaminants: hexokinase < 0.0001 %; glucose 6-phosphate dehydrogenase < 0.0002 %; phosphomannose isomerase 0.003 %; α-glucosidase < 0.00001 %; and ?-glucosidase; < 0.0003 %. Stable at 4°C for > 4 years.