Open AccessThe Stimulation of Liver Phosphorylase b by AMP, Fluoride and Sulfate
Author(s) -
STALMANS Willy,
HERS HenriGéry
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb04144.x
Subject(s) - glycogen phosphorylase , phosphorylase kinase , enzyme , biochemistry , stimulation , chemistry , glycogen , fluoride , endocrinology , biology , inorganic chemistry
1 The activity of liver phosphorylase b from several mammalian species has been studied. The enzyme from rat or mouse has a higher activity than the rabbit enzyme, which is itself more active than pig liver phosphorylase b . 2 The activity of liver phosphorylase b is influenced by anions and by AMP, and these effects are influenced by pH. Fluoride, which is currently added to the assay mixture of phosphorylase a in crude preparations, is about as active as sulfate as a stimulator of phosphorylase b . 3 When assayed at pH 6.1 and in the presence of 0.15 M NaF, the activity of rat liver phosphorylase b reaches 25% of that of the a enzyme; if 1 mM AMP is also present, this value rises to 50%. 4 Methods are described that allow the determination of liver phosphorylase a without interference of b , and the determination of total phosphorylase ( a + b ) in rat liver.