Auxin-Binding Protein in Etiolated Mung Bean Seedlings: Purification and Properties of Auxin-Bindmg Protein-II

摘要

An auxin-binding protein (ABP-II) was purified from the extract of etiolated mung bean seedlings by affinity chromatography on 2,4-D-linked Sepharose 4B and by gel filtration on Sepharose 4B and Sephacryl S-200. The molecular weight was estimated to be about 190,000 by gel filtration on Sephacryl S-200. ABP-II gave a single band corresponding to a molecular weight of about 48,000 on SDS-polyacrylamide gel electrophoresis. The dissociation constants of ABP-II for 2,4-D determined by amrnonium sulfate precipitation and equilibrium dialysis were 9.5×10−6M and 1.1×10−5M, respectively.14C-2,4-D-binding to ABP-II was reversible and inhibited by addition of IAA, naphthalene-1-acetic acid, 2,4,5-trichlorophenoxyacetic acid orp-chlorophenoxyisobutylic acid to the assay mi