Mohapatra S K, Duraiswami S, Chari S
Mol Cell Endocrinol. 1985 Jul;41(2-3):187-96. doi: 10.1016/0303-7207(85)90022-x.
In light of current discussions on multiple forms of inhibin, it was thought of interest to ascertain the identity of the postulated 'iso-hormones' of bull seminal plasma inhibin (Chari et al., 1978). By subjecting the biologically active fraction, obtained by Sephadex G-100 gel filtration of bull seminal plasma acetone powder, to extensive dialysis in distilled water adjusted to pH 5.8, it was possible to remove the bulk of inert protein as a precipitate. The resulting active preparation could be readily fractionated by preparative iso-electric focusing in the pH range 4.0-6.5 yielding 2 distinct homogeneous peptides, alpha and beta, capable of suppressing hCG-induced uterine weight increase in immature mice, in a 'reversed Steelman-Pohley' assay design. However, of these, alpha alone was able to suppress post-castrational serum gonadotropin rise in appropriate animal models. This peptide is highly acidic in nature (iso-electric point congruent to 2.2) and has a molecular weight (Mr) of 18200 and a Stokes radius of 1.90 nm. On the basis of currently available evidence, it is concluded that the molecule consists of a single peptide chain.
鉴于目前对多种形式抑制素的讨论，确定公牛精浆抑制素假定的“同工激素”（Chari等人，1978年）的身份被认为是有意义的。通过对经葡聚糖G - 100凝胶过滤公牛精浆丙酮粉获得的生物活性部分，在pH值调至5.8的蒸馏水中进行广泛透析，有可能以沉淀形式去除大部分惰性蛋白质。所得活性制剂可通过制备性等电聚焦在4.0 - 6.5的pH范围内轻松分级，得到两种不同的均一肽，α和β，在“反向斯蒂尔曼 - 波赫利”试验设计中能够抑制未成熟小鼠中hCG诱导的子宫重量增加。然而，其中只有α能够在合适的动物模型中抑制去势后血清促性腺激素的升高。这种肽本质上是高度酸性的（等电点约为2.2），分子量（Mr）为18200，斯托克斯半径为1.90 nm。根据目前可得的证据，得出该分子由单一肽链组成的结论。
