Purification and characterization of wheat and pine small basic protein substrates for plant calcium-dependent protein kinase

Gideon M. Polya, Shubhra Chandra, Roland Chung, Gregory M. Neumann, Peter B. Höj

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A wheat basic protein (WBP) was purified to homogeneity from wheat germ by a protocol involving extraction, centrifugation, batchwise elution from carboxymethylcellulose (CM-52), acidification with trifluoroacetic acid, neutralization and HPLC on a SP5PW cation exchange column. WBP is a 10 kDa protein and is phosphorylated on serine residues by wheat germ Ca2+-dependent protein kinase (CDPK). [32P]phosphoWBP exactly comigrates with WBP on SDS-PAGE. WBP does not inhibit either wheat germ CDPK or calmodulin-dependent myosin light chain kinase. Apart from histone H1, WBP is the best endogenous substrate yet found for wheat embryo CDPK. A 12 kDa pine basic protein (PBP) was purified to homogeneity from seeds of stone pine (Pinus pinea L.) by a simple procedure involving batchwise elution from carboxymethylcellulose and cation exchange HPLC. PBP is also a good substrate for CDPK and is phosphorylated on Ser residues. N-terminal sequencing of WBP and PBP revealed that these proteins are homologous to a family of small basic plant proteins having a phospholipid transfer function. © 1992.
Original languageEnglish
Pages (from-to)273-280
Number of pages8
JournalBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology
Issue number3
Publication statusPublished - 17 Apr 1992


  • (Pine)
  • (Wheat)
  • Calcium-dependent protein kinase
  • Phospholipid transfer protein
  • Protein purification

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