Further studies of myometrial bradykinin receptor-like binding

[125I-Tyr1]Kallidin (T1K), a bradykinin (BK) analog with biological potency comparable to BK, was used as a probe for BK receptor-like binding from bovine uterine myometrium. BK binding exhibited a high affinity, Kdissoc = 1.65 X 10(-10) M. The specificity of T1K binding was examined with forty-four BK analogs. Comparison of the binding inhibitory potencies with the relative biological potencies of these analogs on isolated rat uterus resulted in a good correlation, r = 0.87. BK binding activity was solubilized with CHAPS, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, a zwitterionic detergent. The solubilized binding activity exhibited a BK binding affinity, Kdissoc = 2.25 X 10(-10) M, and a specificity for three 125I-labeled kinins similar to those of the particulate BK receptor-like binding activity.