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The kinetic properties of rabbit red blood cell hexokinase in different buffer systems have been studied. At pH 8.0 the reaction velocity (v) is about 30% higher in glycylglycine compared to Tris, Tea, Hepes or ammonium acetate buffers. The enzyme stability, heat-dependence and spectral properties of the enzyme are also affected by the buffer utilized. None of the following kinetic properties of red blood cell hexokinase varies with pH in the range 6.8-8.5: Km of glucose; Km of ATP and Ki of glucose 6-phosphate.

In human erythrocytes, in the absence of specific enzymes, G1,6P2 synthesis and degradation are carried out by phosphoglucomutase PGM2 isoenzymes. The results presented, obtained by using partially purified preparations of these enzyme forms, suggest that erythrocyte G1,6P2 may play a crucial role in the physiological interconversion of several important sugar monophosphates.