Measurement of glucose 6-phosphate penetration into liver microsomes. Confirmation of substrate transport in the glucose-6-phosphatase system

The specificity of glucose 6-phosphatase of intact liver microsomes.

The glucose-6-phosphatase system.

Glucose-6-phosphatase (G6Pase), an enzyme found mainly in the liver and the kidneys, plays the important role of providing glucose during starvation. Unlike most phosphatases acting on water-soluble compounds, it is a membrane-bound enzyme, being associated with the endoplasmic reticulum. In 1975, W. Arion and co-workers proposed a model according to which G6Pase was thought to be a rather unsp...

Direct Evidence for the Involvement of Two Glucose 6-Phosphate-binding Sites in the Glucose-6-phosphatase Activity of Intact Liver Microsomes

S 5627 is a synthetic analogue of chlorogenic acid. S 5627 is a potent linear competitive inhibitor of glucose 6-phosphate (Glc-6-P) hydrolysis by intact microsomes (Ki 5 41 nM) but is without effect on the enzyme in detergentor NH4OH-disrupted microsomes. H-S 5627 was synthesized and used as a ligand in binding studies directed at characterizing T1, the Glc-6-P transporter. Binding was evaluat...

Determination of liver microsomal glucose-6-phosphatase.

A procedure for the determination of liver microsomal glucose-6-phosphatase is described. Homogenization and ultracentrifrigation were used to prepare a precipitate whose character was defined by monitoring the desire enzyme activity which serves as a marker. Activity of the enzyme was determined by means of a sensitive colorimetric reaction for the product, inorganic phosphate. Non-enzymatic h...

Liver Microsomal Glucose 6 - Phosphatase , Inorganic Pyrophosphatase , and Pyrophosphate - Glucose

Recently, we (1) described experiments which strongly supported the common identity of glucose 6-phosphatase,’ inorganic pyrophosphatase, pyrophosphate-glucose phosphotransferase, and mannose B-phosphate-glucose phosphotransferase activities present in a preparation obtained by ammonium sulfate fractionation of deoxycholate-dispersed rat liver microsomes. Previously, Segal, Washko, and Lee (2, ...