Assay of Tissue Phosphoglucomutase

Although several values for tissue phosphoglucomutase activites are recorded in the literature, such determinations have been performed without the addition of the coenzyme, a-glucose 1,6-diphosphate (l-3), and occasionally without explicit designation of the optimal concentrations of either or both of the known activators, Mg++ and amino acid (2, 3). Although some of these latter factors have been previously considered (4), the present paper is concerned with the extent to which added coenzyme influences the mutase activity of tissue homogenates and the conditions under which coenzyme and the other activating compounds give maximal phosphoglucomutase activity and hence yield a precise method of assay for this enzyme in tissue.