The synthesis and study of some potential affinity labeling reagents for estrogen receptors

The influence of the following affinity labeling reagents on the binding of tritiated estradiol-17 beta (E) by human and calf uterine cytosols was studied: 11 beta-chloromethylestradiol (ORG4333), 2-azidoestradiol (2A-E), 4-azidoestradiol (4A-E), 3-azidohexestrol (3A-H), estradiol-17 beta 17-bromoacetate (E-17BrAc), 6-[O-carbo-(2'-chloroethoxy)methyl] oximinoestradiol (6-CMOEtC1), 17-[O-carbo-(2'-chloroethoxy) methyl] oximinoestrone (17-CMOEtCl), 2-di (2'-hydroxy-3'-chloropropyl)aminoestradiol (E-Mustard). For the human uterine estrogen receptor the relative binding affinity decreased in the order E greater than ORG 4333 greater than E-17BrAc greater than 3A-H greater than 2A-E greater than 4A-E greater than 6-CMOEtCl greater than E-Mustard greater than 17-CMOEtCl. The binding characteristics of the calf uterine estrogen receptor were qualitatively similar, but quantitatively different. ORG 4333 appeared to form a highly stable association with the receptors, but alkylation of the protein could not be conclusively demonstrated.