Fig. 1.

Saturation data for the [³H]estradiol binding to estrogen receptors from calf uteri. Data points obtained from Fig. 2 in Notides et al. (1981) were fitted assuming one or two affinity states (dashed line) or a two-state dimer. F test indicated that a significant improvement is obtained by assuming the two-state dimer receptor model; thus, in Table 1, only the parameter values obtained assuming dimers are shown.