A surprising increase in the affinity of estrogen for rat alpha-fetoprotein after it is treated with N-ethylmaleimide.
Incubation of rat alpha-fetoprotein (AFP) with mM concentrations of N-ethylmaleimide (MalNEt) at 22 degrees, pH7.8 for several hours yields a form of AFP with an equilibrium dissociation constant of 0.1 nM for estrone. This affinity for estrone is about 10 fold higher than that for untreated rat AFP. MalNEt-treated AFP still binds inhibitors and substrates of serine proteases suggesting that the binding of these compounds to AFP does not involve an interaction with a thiol group. MalNEt-treated AFP may be useful for studying the mechanism of estrogen action in vitro and in vivo, estrogen-protein interactions, and the functioning of AFP.
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Baker
D000653:Amniotic Fluid; D000818:Animals; D004958:Estradiol / Q000378:metabolism*; D004970:Estrone / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology*; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011247:Pregnancy; D011485:Protein Binding; D051381:Rats; D000509:alpha-Fetoproteins / Q000378:metabolism*
D000509:alpha-Fetoproteins; D004970:Estrone; D004958:Estradiol; D005033:Ethylmaleimide