Which type of covalent modification can be seen in glycogen synthase?

Glycogen synthase exists in at least two forms; a phosphorylated form, arising from the covalent modification of serine residues by ATP; and a dephosphorylated form, which can be obtained using phosphatase on the phosphorylated form (Figure 2).

How is glycogen synthase modified?

Glycogen synthase is regulated by both allosteric factors (primarily glucose 6-phosphate) and covalent modification by reversible phosphorylation and dephosphorylation leading to inactivation and activation of GS, respectively.

What converts G6P to G1P?

Cytosolic phosphoglucomutase (PGM) catalyses the reversible conversion of glucose 6-phosphate (G6P) to glucose 1-phosphate (G1P) (Drago et al. 1991). Two PGM isoenzymes, both monomers, have been identified which both require Mg2+ as cofactor.

What is the difference between covalent and allosteric modulation?

Which is the following is the most important difference between covalent and allosteric modulation of proteins? Allosteric modulation requires a phosphatase and covalent modulation requires a kinase.

Which kinase regulates glycogen synthase by covalently adding a phosphate group to the enzyme?

Glycogen synthase is directly regulated by glycogen synthase kinase 3 (GSK-3), AMPK, protein kinase A (PKA), and casein kinase 2 (CK2). Each of these protein kinases lead to phosphorylated and catalytically inactive glycogen synthase.

What is glycogen synthase?

n. An enzyme that catalyzes the transfer of glucose from UDP-glucose to glycogen.

What converts G6P to F6P?

phosphoglucose isomerase
Metabolic Pathways in the Human Body Glucose-6-phosphate (G6P) is changed into fructose-6-phosphate (F6P) by phosphoglucoisomerase (phosphoglucose isomerase) in the second step. This reaction also requires Mg2+. F6P can enter the glycolytic pathway from the next point. This reaction has a low free energy charge.

What is the role of phosphoglucomutase?

Phosphoglucomutase (PGM) is a key enzyme in glycolysis and gluconeogenesis, regulating both glycogen and trehalose metabolism in insects.

How does covalent modification control enzyme activity?

Enzymes can be regulated by transfer of a molecule or atom from a donor to an amino acid side chain that serves as the acceptor of the transferred molecule. Another way of regulating an enzyme is by altering the amino acid sequence itself by proteolytic cleavage.