Kugler P
Histochemistry. 1982;74(2):247-61. doi: 10.1007/BF00495834.
Biochemical fluorometric methods were used to investigate aminopeptidase A (APA; E.C.3.4.11.7) in the rat kidney homogenate and glomeruli and to compare it with aminopeptidase M (APM; E.C.3.4.11.2). It is shown that APA is a calcium-ion-dependent enzyme, while APM is not. To clarify the functional importance of APA and APM in the kidney, their activities were measured under the influence of angiotensins. Fluorimetric measurements in renal homogenate (with 2-naphthylamide derivatives as substrates), which represents mixed-enzyme tissue preparations containing a variety of peptidases besides APA and APM, showed a Km of 0.13 mM for APA and competitive inhibition of ANG II (K1 = 0.015 mM), and a Km of 0.24 for APM and competitive inhibition by ANG III (K1 = 0.003 mM). The remaining two angiotensins showed non-competitive inhibition of APA (ANG I, III) and APM (ANG I, II) in this preparation. For comparison purposes, fluorometric measurements were performed in microdissected glomeruli which contain only APA. A Km of 0.23 mM for the APA and a competitive inhibition of APA by ANG I and II were determined. Thus it was possible to show biochemically that APA is equivalent to angiotensinase A and that both APA and APM participate in angiotensin degradation in the kidney. APA initiating the breakdown of ANG I and II, and APM possibly continuing it in sequential fashion.
采用生化荧光法研究大鼠肾脏匀浆和肾小球中的氨肽酶A（APA；E.C.3.4.11.7），并将其与氨肽酶M（APM；E.C.3.4.11.2）进行比较。结果表明，APA是一种钙离子依赖性酶，而APM不是。为了阐明APA和APM在肾脏中的功能重要性，在血管紧张素的影响下测量了它们的活性。在肾脏匀浆中（以2-萘酰胺衍生物为底物）进行荧光测量，肾脏匀浆是一种混合酶组织制剂，除了APA和APM外还含有多种肽酶，结果显示APA的Km为0.13 mM，对血管紧张素II有竞争性抑制作用（K1 = 0.015 mM），APM的Km为0.24，对血管紧张素III有竞争性抑制作用（K1 = 0.003 mM）。在该制剂中，其余两种血管紧张素对APA（血管紧张素I、III）和APM（血管紧张素I、II）表现出非竞争性抑制作用。为了进行比较，在仅含有APA的显微解剖肾小球中进行了荧光测量。测定了APA的Km为0.23 mM，血管紧张素I和II对APA有竞争性抑制作用。因此，从生化角度可以证明APA等同于血管紧张素酶A，并且APA和APM都参与肾脏中的血管紧张素降解。APA启动血管紧张素I和II的分解，而APM可能以顺序方式继续进行分解。
