A DIALYSIS ELECTRODE FOR GLYCEROL

A dialysis electrode for the measurement of -glycerol is described. The electrode consists of a platinum wire inserted into the tip of a dialysis probe. The electrode uses the enzymes glycerol kinase (E.C. 2.7.1.30) and L-glycerol-3-phosphate oxidase (E.C. 1.1.3.21) held stationary in the probe cavity. A linear response to glycerol was obtained up to 0.2 mM. Responses to glycerol and L-glycerol-3-phosphate are analysed ar-cording to the membrane electrode theory developed by Albery and Bartlett for enzyme electrodes. The analysis indicates that the unsaturated responses for both glycerol and L-glycerol-3-phosphate are controlled by diffusion of substrate through the membrane. The effect of the concentration of ATP, the cofactor for glycerol kinase, is also examined.