Ca2+-dependent protein kinase from the halotolerant green alga Dunaliella tertiolecta: Partial purification and Ca2+-dependent association of the enzyme to the microsomes

摘要: Ca(2+)-dependent protein kinase (CDPK) was purified 900-fold from the soluble fraction of Dunaliella tertiolecta cells by ammonium sulfate precipitation, DEAE-Toyopearl, phenyl-Sepharose, and hydroxylapatite column chromatography. The CDPK activated micromolar concentration Ca2+ required neither calmodulin nor phospholipids for its activation. enzyme phosphorylated casein, myosin light chain, histone type III-S (histone H-1), but did not phosphorylate protamine phosvitin. Km values ATP casein were 11 microM 300 micrograms/ml, respectively. Phosphorylation inhibited antagonists, calmidazolium, trifluoperazine, compound 48/80, affected calmodulin. bound to phenyl-Sepharose in presence eluted ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid (EGTA). This suggests that hydrophobicity increased Ca2+. also microsomes isolated released EGTA, suggesting possibility vivo association enzyme. many proteins few cytosol, if at all.