Open AccessAuxin Receptors of Maize Coleoptile Membranes Do Not Have ATPase Activity
Author(s) -
John W. Cross,
Winslow R. Briggs,
Ulrike Dohrmann,
Peter M. Ray
Publication year - 1978
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.61.4.581
Subject(s) - coleoptile , auxin , receptor , membrane , atpase , biochemistry , chemistry , size exclusion chromatography , biology , biophysics , enzyme , gene
Membrane-localized auxin-binding sites from coleoptiles and primary leaves of Zea mays L. which may be auxin receptors can be fully solubilized by 1 to 1.5 mg of Triton X-100 per mg of membrane protein (about 1 mg per gram of original tissue fresh weight), while 70% of the basal (Mg(2+))-ATPase and 85% of the K(+)-stimulated (Mg(2+))-ATPase (pH 6) remain pelletable. Gel exclusion chromatography on Bio-Gel A-1.5m indicates that the solubilized receptors occur as detergent-protein micelles of about 90,000 daltons equivalent molecular weight. Solubilized ATPase activities occur (a) as very large particles excluded from the gel, and (b) as particles of a size substantially smaller than the particles that exhibit auxin binding. The auxin-binding receptor therefore appears not to be an ATPase.