Kinetics of Glycerol Kinases from Mammalian Liver and Candida mycoderma

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Abstract
Glycerol kinase (ATP: glycerol phosphotransferase, EC 2.7.1.30) has been purified from rat, beef and human liver. Glycerol kinase from Candida mycoderma was also investigated.The kinetics with regard to glycerol are of the Michaelis‐type. The Lineweaver‐Burk plots with regard to ATP are non‐linear. The data obtained provide evidence for the ATP‐Mg2− complex as the true substrate and indicate that free ATP is a positive modifier for the enzymes.Inhibition experiments showed no effect of ethanol, acetaldehyde, acetate, d,l‐glycerol‐3‐phosphate, fructose‐1,6‐diphosphate or NADH upon the reaction velocities. ADP and AMP are strong inhibitors of the enzyme.The inhibition by AMP has been examined. It is concluded that AMP is a negative modifier for glycerol kinase. The inhibition by AMP is counteracted by free ATP. The interaction coefficient for AMP is about one.The kinetic properties of the glycerol kinases examined are to some extent similar to those of phosphoglycerate kinase. The possible physiological significance of the inhibition by AMP is discussed.