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Updated: Aug 4, 2026

Biochemical Titration of Glycogen In vitro
Published on: November 25, 2013
Phosphorylation of glycogen synthase by a bovine thymus protein-tyrosine kinase, p40
A M Mahrenholz1, P Votaw, P J Roach
1Department of Biochemistry, Indiana University School of Medicine, Indianapolis 46223.
Abstract:
Glycogen synthase from rabbit skeletal muscle was found to be phosphorylated by a protein-tyrosine kinase, p40, purified from bovine thymus. The phosphorylation, to a stoichiometry of 0.4-0.5 mol/mol subunit, was specific for a single tyrosine residue in the sequence EEDGERYDEDEE. This acidic sequence has considerable similarity to the site recognized by p40 in erythrocyte band 3 protein. In the analysis of the phosphorylated peptide, it was noted that the sequence -RY(P)- impeded cleavage by either trypsin or automatic Edman degradation.
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