Isolation of Gibberellin-binding Proteins by Aflinity Chromatography

Abstract

Gibberellin-binding proteins (GBPs) were isolated from a crude extract of etiolated maize seedlings by affinity chromatography on gibberellin A₃(GA₃)-linked enhance-aminohexyl(EAH)-Sepharose 4B. The isolated proteins had a binding activity for [³H]-GA₄. The binding site with dissociation constant of 0. 5μM for GA₄ was detected in the proteins by the binding assay with the procedures of ammonium sulfate precipitation. The binding of [³H]-GA₄ to GBPs was reversible and could be inhibited by the addition of GA₁ and GA₃. An inactive gibberellin, GA₁₃, had no inhibitory effect on the binding of [³H]-GA₄ to GBPs.