The role of auxin-binding protein during growth and development of fruit

点击翻译按钮获取中文摘要

Auxin-binding protein in apple seedling was partially purified by 2, 4-D linked-Sephasrose 4B affinity chromatography and 2 times of Sepharose 4B gel filtration. It had a molecular weight of about 400 KDa and was composed of subunit bands of 56 KDa ana 15 KDa by SDS-PAGE, which appeared in proportion to the strength of 6binding activity. The dissociation constant by Scatchard plot was 7.7X1O^<-6> M. This binding protT4n is similar to ABP-I from mung bean seedling. The binding activity to ^<14>C-IAA was completely inhibited by 2, 4-D and NAA, and inhibited to about 50% by PCIB of antiauxin. Auxin-binding protein in melon seedling partially purified by the same procedure showed the equal activity between both assay methods of an ammonium sulfate precipitation and an equilibrating dialysis. The protein had a molecular weight of 155 KDa and a dissociation constant of 4.8X1O^<-6> M, and combined more than one molar IAA to one molar protein. This binding protein from mellon seedling is like ABP-II from mung bean seedling.The function about two kinds of the auxin-binding protein was not investigated in detail through the present experiment. However, we can suggest firmly these auxin binding proteins possess the characteristics as an auxin receptor, as defined by the specificity for substrate, the saturation of reaction to substrate concentration and the reversibility of reaction.