Selective dephosphorylation of histone H1 by nuclear phosphatases
The aim of this study was to characterize the sites of H1 phosphorylated by the cAMP-dependent protein kinase (kinase A) and the CaS phospholipid-dependent protein kinase (kinase C) and to study their dephosphorylation by nuclear protein phosphatases. H1 was phosphorylated on a ser residue to approx. 1 mole (TSP)/mole H1 with either kinase A or C. The sites of phosphorylation were differentiated by digestion of the H1 by thrombin or N-bromosuccinimide. Phosphopeptide maps on reversed phase HPLC and gel filtration HPLC clearly showed that the kinase C phosphorylated a different site than the well characterized kinase A site. H1, phosphorylated by kinase C or kinase A, was used as a substrate for the nuclear phosphatases. The nuclear phosphatases were purified from salt extracted rat liver chromatin and separated into 2 forms based on heat-stable inhibitor sensitivity and polycation stimulation. Polycation-stimulated phosphatase rapidly dephosphorylated the kinase C site and slowly dephosphorylated the kinase A site. The inhibitor-sensitive enzyme showed little activity toward either site under standard assay conditions.
- Research Organization:
- Medical College of Ohio, Toledo
- OSTI ID:
- 6285738
- Report Number(s):
- CONF-870644-; TRN: 87-028675
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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HISTONES
PHOSPHORYLATION
PHOSPHATASES
ENZYME ACTIVITY
FRACTIONATION
LIQUID COLUMN CHROMATOGRAPHY
PHOSPHORUS 32
TRACER TECHNIQUES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL REACTIONS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUCLEOPROTEINS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques