Molybdate and the molecular properties of the vervet monkey estrogen receptor

The Vervet monkey (Cercopithecus aethiops pygerythrus) uterine estrogen receptor was partially characterised. The effect of the molybdate oxyanion on various molecular properties of the receptor was investigated. Molybdate appeared to affect the subunit structure and apparent heterogeneity of the receptor. Anion exchange chromatography of uterine cytosols yielded two ligand binding subunits in a 1:1 ratio in the absence of sodium molybdate, while only a single labelled complex could be demonstrated in cytosols prepared in molybdate containing buffers. Chromatofocussing of the nonstabilized cytosols revealed substantial receptor heterogeneity (7 peaks) while a much simpler pattern (2 peaks) could be observed in the presence of the molybdate. Likewise, iso-electric focussing of labelled cytosols on agarose gels yielded at least 3 high affinity binding components (pI:6.8, 6.2, 5.9) in the absence and only one major band in the presence of sodium molybdate (pI 5.9).