The calmodulin-stimulated ATPase of maize coleoptiles forms a phosphorylated intermediate.
The calmodulin-stimulated ATPase of maize coleoptiles is a 140,000 Mr polypeptide. In the present study, formation of a phosphorylated intermediate by the enzyme is demonstrated. Phosphorylation is sensitive to chasing with unlabelled ATP and to hydroxylamine; lanthanum enhances its intensity while calmodulin enhances phosphorylation in the presence of lanthanum but not in its absence. Ethyleneglycol-bis-(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA) inhibits phosphorylation of the purified enzyme, but microsome preparations give a band of phosphorylation of 153,000 Mr in its presence. This latter phosphorylated band was not abolished after a variety of permeabilising treatments in the presence of Triton X-100; phosphorylation of the enzyme was absent when sodium deoxycholate was used as the solubilising detergent. The identity of the 153,000 Mr band is discussed.
Briars
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Department of Plant Sciences, University of Oxford, U.K.
Evans
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D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology*; D003840:Deoxycholic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D008970:Molecular Weight; D017830:Octoxynol; D010766:Phosphorylation; D010944:Plants / Q000201:enzymology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D003313:Zea mays
D002147:Calmodulin; D006898:Hydroxylamines; D003840:Deoxycholic Acid; D019811:Hydroxylamine; D011092:Polyethylene Glycols; D004533:Egtazic Acid; D007811:Lanthanum; D000255:Adenosine Triphosphate; D017830:Octoxynol; D000251:Adenosine Triphosphatases; D002118:Calcium