Multiplicity of Adenosine 3′,5′-Monophosphate-dependent Protein Kinases from Rat Liver and Mode of Action of Nucleoside 3′,5′-Monophosphate

摘要: Abstract Two fractions of adenosine 3',5'-monophosphate (cyclic AMP)-dependent protein kinase (protein B1 and B2) one fraction cyclic AMP-independent B0) are resolved partially purified from rat liver cytosol treated with diisopropyl fluorophosphate by ammonium sulfate fractionation followed DEAE-Sephadex hydroxylapatite column chromatography. Analysis gel filtration on a Sephadex reveals that B0 shows single peak themolecular weight approximately 3 x 104, whereas is mixture two, major minor, species AMP-dependent kinases the molecular weights 1.8 105 1.2 105, respectively. However, minor appears to be an artifact due proteolysis during isolation procedure. Protein B2 also multiple ranging 1.0 up more than 2.0 105. This heterogeneity does not seem represent simply Each shown inactive form kinase, activity which inhibited association regulatory (R-protein). R-protein per se catalytically inactive. Cyclic AMP activates such binding molecule in allosteric manner, resulting release active kinase. All thus released both indistinguishable B0, show 104. The similar kinetic properties behave identical manner upon chromatography column. These stimulated nor nucleotide, phosphorylate same specific seryl threonyl residues histone. An available evidence suggests differ each other their associated R-proteins, although exact identity may explored further investigations. reconstituted R-proteins 1.5 9 latter probably proteolysis. cytosol. attempts reconstitute have been unsuccessful. Most unstable decomposed smaller about 4 closely properties, but affinities for slightly different.