Online edition:ISSN 2758-089X

Effect of Sodium Molybdate on Androgen Binding to Its Receptor from Shionogi Carcinoma 115

The effects of molybdate on the binding characteristics of androgen receptor from the androgen-dependent mouse tumor (Shionogi carcinoma 115) with 17/β-hydroxy-5α-androstan-3-one were studied by the charcoal adsorption method. The dissociation constant (Kd) was (4.65±0.54) ×1O-11 M in the presence of 10―12 mM sodium molybdate, which was one order of magnitude lower than the value without molybdate ((4.54±0.72)× 10-10 M). Since the half life of the binding activity of unbound receptor was extended from 10 h to 75 h by adding molybdate, the effects of chaotropic reagents on binding were studied in the presence of molybdate. KC1 (0.3 -1.0 M) remarkably increased Kd without affecting the maximum binding capacity or the dissociation rate. KSCN (>0.1 M) had no effect on Kd but increased the dissociation rate, and while at concentrations at or above 0.5 M it completely inhibited the androgen binding to the cytosol receptor. Urea (0.5-2.0 M) increased Kd proportionally to the increase in the dissociation rate. Kd was also increased by 0.2-0.5 M guanidine, but the maximum binding capacity was reduced.

Nohno T, et al