Purification and characterization of a thylakoid protein kinase
Control of state transitions in the thylakoid by reversible phosphorylation of the light-harvesting chlorophyll a/b protein complex of photosystem II (LHC-II) is modulated by a kinase. The kinase catalyzing this phosphorylation is associated with the thylakoid membrane, and is regulated by the redox state of the plastoquinone pool. The isolation and partial purification from spinach thylakoids of two protein kinases (CPK1, CPK2) of apparent molecular masses 25 kDa and 38 kDa has been reported. Neither enzyme utilizes isolated LHC-II as a substrate. The partial purification of a third protein kinase (LHCK) which can utilize both lysine-rich histones (IIIs and Vs) and isolated LHC-II as substrate has now been purified to homogeneity and characterized by SDS-polyacrylamide gel electrophoresis as a 64 kDa peptide. From a comparison of the two isolation procedures we have concluded that CPK1 is indeed a protein kinase, but has a lower specific activity than that of LHCK. 8 refs., 4 figs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA). Biology Dept.
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5206232
- Report Number(s):
- BNL-38633; CONF-860808-2; ON: DE86016164
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
FRACTIONATION
ISOTOPES
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MEMBRANES
NUCLEI
ODD-ODD NUCLEI
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PHOTOSYNTHETIC MEMBRANES
RADIOISOTOPES
SEPARATION PROCESSES
TRANSFERASES