Partial purification and characterization of a calcium-dependent protein kinase in rice leaves.
A protein from rice leaves, which was partially purified by sequential chromatography on DE52, MONO-Q and Superose 12, presented calcium-dependent protein kinase (CDPK) activity. This protein kinase phosphorylated the substrate, histone III-S, in a Ca(2+)-dependent manner and the half-maximum concentration of Ca2+ to protein kinase activity (EC50) was 1 microM. This phosphorylation was independent of phosphatidylserine and a phorbol ester. The apparent M(r) of the protein kinase, as determined by phosphorylation in SDS-polyacrylamide gel containing histone III-S, was 45 k. This kinase was found to react differently from other protein kinases, such as protein kinase C from rat brain or CDPK from soybean leaves, owing to the absence of a phospholipid or phorbol ester dependency. CDPK phosphorylated three endogenous proteins as detected by in vitro phosphorylation on two-dimensional PAGE.
Karibe
H
H
Department of Molecular Biology, National Institute of Agrobiological Resources, Ibaraki, Japan.
Komatsu
S
S
Hirano
H
H
D000818:Animals; D001921:Brain / Q000201:enzymology; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D007700:Kinetics; D012275:Oryza / Q000201:enzymology*; D010766:Phosphorylation; D018515:Plant Leaves; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism; D011494:Protein Kinases / Q000302:isolation & purification* / Q000378:metabolism*; D051381:Rats; D013025:Glycine max / Q000201:enzymology; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D011493:Protein Kinase C; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases