Resolution of a higher plant protein kinase similar to the catalytic subunit of cyclic AMP-dependent protein kinase

G. M. Polya, R. Chung, J. Menting

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A protein kinase partially purified from petunia (Petunia hybrida var. Old Glory Blue) petals by cation exchange and gel filtration catalyses the phosphorylation of Kemptide (LRRASLG), a synthetic peptide substrate for cAMP-dependent protein kinase. The Kemptide kinase (molecular weight 30,000) is a basic protein and is inhibited by the regulatory subunit of bovine cAMP-dependent protein kinase in a cAMP-reversible fashion as is the catalytic subunit of animal cAMP-dependent protein kinase. The Kemptide kinase is inhibited by preparations of inhibitor proteins of mammalian cAMP-dependent protein kinase but is not affected by Ca2+-calmodulin, cyclic AMP or low concentrations of heparin. The Kemptide kinase is Ca2+-independent. However, a basic Ca2+-dependent protein kinase (molecular weight 50 000) that phosphorylates casein, histones and myosin light chain-derived synthetic peptide (KKRAARATSNVFA-NH2), but not Kemptide, is also present in petunia petals. © 1991.
Original languageEnglish
Pages (from-to)37-45
Number of pages9
JournalPlant Science
Issue number1
Publication statusPublished - 1 Jan 1991


  • 3′,5′-cyclic AMP
  • Ca 2+
  • Petunia hybrida
  • protein kinase

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