Characterization studies of glucose dehydrogenase.

Porcine liver beta-D-glucose dehydrogenase has been isolated using Triton X-114 to release it from the endoplasmic reticulum. The purified enzyme contains a limited amount (1.7%) of lipid material, including cholesterol, fatty acids, mono and diglycerides, phosphatidylcholine, phosphatidylethanolamine, and cholesterol esters. This enzyme is a tetrameric protein containing an extensive number of hydrophobic residues. This form of glucose dehydrogenase is capable of turning over both beta-D-glucose and alpha-D-glucose-6-phosphate in vivo as indicated from a steady state kinetic analysis at 37 degrees C.