DETERMINATION OF LIVER MICROSOMAL GLUCOSE-6-PHOSPHATASE

Abstract

A procedure for the determination of human liver microsomal glucose-6-phosphatase was described. Homogenization and ultracentrifugation were used to prepare a precipitate whose character was defined by monitoring the desired enzyme activity which serves as a marker. Activity of the enzyme was determined by means of a sensitive colorimetric reaction for the product, Pi. Non-enzymatic hydrolysis problems with the substrate were minimized in this procedure by the masking action of citrate. The final heteropoly blue color appeared to be considerably sensitized by interaction of phosphomolybdous ion with arsenite. The stability of the relatively labile enzyme was ensured by chelating any metals present with EDTA. The procedure appeared to be useful as an aid in the diagnosis of Type 1 glycogenosis, a glycogen storage disease called Von Gierke''s disease.