Purification and properties of bovine myocardial phosphorylase phosphatase (protein phosphatase C)

• Published in: Archives of biochemistry and biophysics Vol. 191; no. 2; pp. 638 - 646
• Main Authors: Killilea, S.Derek, Aylward, James H., Mellgren, Ronald L., Lee, Ernest Y.C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.1978
• Subjects: Animals; Cattle; Histones; Molecular Weight; Myocardium - enzymology; Phosphoprotein Phosphatases - isolation & purification; Phosphorylase Phosphatase - isolation & purification; Phosphorylase Phosphatase - metabolism; Protamines; Rabbits; Substrate Specificity
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/0003-9861(78)90402-2

Phosphorylase phosphatase was purified to homogeneity from bovine myocardium by the procedure of Brandt et al. ( Brandt, H., Capulong, Z. L., and Lee, E. Y. C., (1975) J. Biol. Chem. 250, 8038–8044). The purified enzyme consists of a single polypeptide chain of M r, 34,800 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The K m for phosphorylase a was 2.9 μ m and at V max, the enzyme had a turnover number of 11.7 mol phosphorylase a (dimer) converted/mol phosphatase/s. Phosphorylated histone and protamine were also substrates for this phosphatase. The K m for histone was 46 μ m (based on incorporated 32P i and at V max a turnover number of 3.3 mol phosphate released/mol phosphatase/s was found. In general, the properties of the bovine phosphorylase phosphatase closely resemble those found for the rabbit liver enzyme.