Amino acid sequence of the phosphorylated site in rabbit liver glycogen phosphorylase

Influence of Thyroid Hormone on Glycogen Metabolism in Rat Liver

“…According to the above-mentioned mechanisms, the metabolites are divided into four groups; (1) activating effectors of glycogen synthetase 1968a, b; Glinsmann et al, 1970) (2) inhibiting effectors of glycogen synthetase a: AMP, ATP, cAMP and glycogen (De Wulf and Hers, 1968a, b;De Wulf et al, 1970;Glinsmann and Hem, 1969;Bishop and Lamer, 1969), (3) activating effectors of phosphorylase a: AMP, cAMP and glycogen (Wolf et al, 1970;Lowry et al, 1964;Monod et al, 1965;Morgan and Parmeggiani, 1964;Stalmans et al, 1970;Nolan et al, 1964;Walsh et al, 1968) and (4) inhibiting effectors of phosphorylase a: glucose, G6P, ATP and ADP (De Wulf and Hers, 1968a;Glinsmann et al, 1970;Parmeggiani, 1962, 1964). It is worth noting that the range of changes in metabolite concentrations in the various thyroid states is close to effector concentrations which modulate the enzyme activities including glycogen synthetase phosphatase, phosphorylase phosphatase, glycogen synthetase kinase and phosphorylase kinase (See the above references).…”

Thermodynamic Characterization of 5′-AMP Binding to Bovine Liver Glycogen Phosphorylase a

“…Furthermore, changes in tertiary structure of muscle isozyme associated with effector binding are accompanied by changes in the quaternary structure (39). Nevertheless, some phosphorylases, such as those from pig muscle (40) and rabbit liver (8), are less prone to form tetramers on activation. If the binding of an effector produces a change in the state of protein oligomerization, an enthalpic contribution arising from this change would show up in the calorimetric data.…”

“…This nucleotide binds tightly and cooperatively to the inactive muscle isozyme (3,4) but is a weak activator of liver phosphorylase b and binds to it weakly and noncooperatively (5,6). The phosphorylated forms do not depend upon 5Ј-AMP for their activity, although this can be enhanced by the addition of 5Ј-AMP in both the muscle (7) and liver (8,9) isozymes.…”

The control of glycogen metabolism in the liver

“…The liver contains a phosphorylase phosphatase [ 1 ] and a phosphorylase kinase [2] ; the latter enzyme is more active in the presence of cydic AMP (see section 6). The liver phosphophosphorylase (phosphorylase a) is the active form of the enzyme; its activity is increased by 15 to 40% upon the addition of 10 -3 M AMP [3,4]. The dephosphoenzyme (phosphorylase b) is completely inactive in the absence of AMP; its activity in the presence of the nucleotide is nearly zero in pig or rabbit liver [5], but reaches 15% of phosphorylase a in dog liver [3] and 25% in mouse liver [6].…”