[Properties and isoenzyme contents of glucose-6-phosphatase of normal and tumor cell microsomes].

Studies on the properties and isoenzymic content of glucose-6-phosphatase (E. C. 3.1.3.9.) of normal and tumor cells microsomes allowed the following conclusion to be made: the localization of the enzyme in the membranes of endoplasmatic reticulum of both types of cells is identical. The tumor microsomes are characterized (irrespective of the blastomogenic factor inducing them) by a decreased activity of the enzyme at pH 6.75, a relatively increased activity of the latter at pH 7.5. Solubilization of the enzyme was performed by a new technic i. e. the acetone treatment of microsomes. Rechromatography of most active fractions on Sephadex G-200 has revealed less number of the enzyme isoforms of tumor cell microsomes.