Barrett J D, Eggena P, Hidaka H, Sambhi M P
J Clin Endocrinol Metab. 1979 Jan;48(1):96-100. doi: 10.1210/jcem-48-1-96.
Human des-angiotensin I renin substrate, a cleavage product of the renin reaction, was generated in plasma and from semipurified renin substrate by exhaustive incubation with renin and was quantitated by a direct RIA. An increase in the Michaelis-Menten constant of the renin-substrate reaction, from 2000 to 5000 ng angiotensin I equivalents of renin substrate/ml, with no change in maximal velocity was observed upon addition of this semipurified protein to plasma. It is suggested that this phenomenon of competitive inhibition of the renin reaction by des-angiotensin I renin substrate accounts for discrepancies in the determination of renin substrate concentration and possibly has physiological significance for feedback inhibition of angiotensin I generation.
人脱-血管紧张素I肾素底物是肾素反应的一种裂解产物，通过与肾素充分孵育在血浆中产生，并从半纯化的肾素底物中产生，通过直接放射免疫分析法进行定量。当将这种半纯化蛋白添加到血浆中时，观察到肾素-底物反应的米氏常数增加，从每毫升2000至5000纳克血管紧张素I当量的肾素底物增加，而最大速度没有变化。有人提出，脱-血管紧张素I肾素底物对肾素反应的这种竞争性抑制现象解释了肾素底物浓度测定中的差异，并且可能对血管紧张素I生成的反馈抑制具有生理意义。
