That amount of enzyme causing an increase in the rate of spontaneous mutarotation of -D-Glucose to -D-Glucose of one micromole per minute at 25C and pH 7.0.
One unit as described as above is equivalent to approximately 0.04 units in a Glucose dehydrogenase-coupled assay at 25C and pH 7.2 or app
Form
A suspension in 80% saturated Ammonium sulphate solution pH 8.0.