NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Partial purification and characterization of a Ca(2+)-dependent protein kinase from pea nucleiAlmost all the Ca(2+)-dependent protein kinase activity in nuclei purified from etiolated pea (Pisum sativum, L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.3 molar NaCl. This protein kinase can be further purified 80,000-fold by salt fractionation and high performance liquid chromatography, after which it has a high specific activity of about 100 picomoles per minute per microgram in the presence of Ca2+ and reaches half-maximal activation at about 3 x 10(-7) molar free Ca2+, without calmodulin. It is a monomer with a molecular weight near 90,000. It can efficiently use histone III-S, ribosomal S6 protein, and casein as artificial substrates, but it phosphorylates phosvitin only weakly. Its Ca(2+)-dependent kinase activity is half-maximally inhibited by 0.1 millimolar chlorpromazine, by 35 nanomolar K-252a and by 7 nanomolar staurosporine. It is insensitive to sphingosine, an inhibitor of protein kinase C, and to basic polypeptides that block other Ca(2+)-dependent protein kinases. It is not stimulated by exogenous phospholipids or fatty acids. In intact isolated pea nuclei it preferentially phosphorylates several chromatin-associated proteins, with the most phosphorylated protein band being near the same molecular weight (43,000) as a nuclear protein substrate whose phosphorylation has been reported to be stimulated by phytochrome in a calcium-dependent fashion.
Document ID
20040090220
Document Type
Reprint (Version printed in journal)
Authors
Li, H. (The University of Texas at Austin 78713 United States)
Dauwalder, M.
Roux, S. J.
Date Acquired
August 21, 2013
Publication Date
January 1, 1991
Publication Information
Publication: Plant physiology
Volume: 96
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: DCB-8716572
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 40-50
NASA Program Space Biology
Non-NASA Center
NASA Discipline Plant Biology