Open AccessSeparation of Rat-Liver Phosphoprotein Phosphatases Active on Phosphorylated Pyruvate Kinase (Type L)
Author(s) -
Vincent P.K. Titanji
Publication year - 1978
Publication title -
upsala journal of medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 41
eISSN - 2000-1967
pISSN - 0300-9734
DOI - 10.3109/03009737809179126
Subject(s) - dephosphorylation , phosphatase , biochemistry , phosphorylation , sephadex , kinase , enzyme , pyruvate kinase , glycogen phosphorylase , microbiology and biotechnology , phosphoprotein , medicine , biology , glycolysis
The substrate specificity of rat liver phosphoprotein phosphatases has been investigated. The enzymes were resolved into three fractions, termed A, B and C, on elution from DEAE-cellulose with apparent molecular weights, as determined by Sephadex G-200 chromatography, of approximately 250 000, 250 000 and 140 000, respectively. All fractions catalyzed the dephosphorylation of calf-thymus phosphohistones, salmon phosphoprotamine and rabbit skeletal muscle phosphorylase a. The major portion of the activity towards these substrates was found in fraction B. The activity towards rat liver phosphopyruvate kinase (type L) resided almost exclusively in fractions B and C. It is concluded that rat liver contains multiple forms of phosphoprotein phosphatases and that phosphatases of fraction B and C are the major activities towards phosphopyruvate kinase.