Phosphorylase kinase phosphorylation of skeletal-muscle troponin T.
Rabbit skeletal-muscle troponin T was phosphorylated by a standard preparation of phosphorylase kinase [Cohen (1973) Eur. J. Biochem. 34, 1--14] and by fractions obtained after chromatography of phosphorylase kinase on phosphocellulose. The original preparation of phosphorylase kinase phosphorylated at least two sites, one of which was serine-1. The second and probably the third sites were presumably located in the peptide flanked by amino-acid residues 147 and 161 of troponin T. Fractions of phosphorylase kinase was adsorbed on phosphocellulose phosphorylated only the second site. Tightly adsorbed fractions possessed high troponin T kinase and phosvitin kinase activities and phosphorylated only serine-1 of troponin T. The results suggest that standard preparations of phosphorylase kinase are contaminated by troponin T kinase, which can phosphorylate serine-1 of troponin T.
D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004340:Drug Contamination; D009124:Muscle Proteins; D010446:Peptide Fragments / Q000032:analysis; D010764:Phosphorylase Kinase / Q000302:isolation & purification*; D010766:Phosphorylation; D014336:Troponin
D000596:Amino Acids; D009124:Muscle Proteins; D010446:Peptide Fragments; D014336:Troponin; D010764:Phosphorylase Kinase