CHAPTER 12 - Renin

Abstract

This chapter provides an overview of rennin. The renin–angiotensin system has been the subject of extensive study since the discovery of the vasopressive action of aqueous kidney extracts. Any assay of renin must take into account the fact that it is an enzyme. In some cases, direct biological measures are used. These methods determine not an activity peculiar to renin but rather the total product of the enzyme-substrate reaction. An important application of the direct assay is in the search for substances that present a renin-like activity in the various tissues and fluids of the body. However, as renin is an enzyme, it is usually assayed indirectly by measuring the final product of the enzyme-substrate reaction, that is, angiotensin or its degradation products. This may be achieved by biological, physicochemical, or immunological means. The most important work on the purification of renin was performed by Haas, Goldblatt, and coworkers. Renin's physical and chemical properties have been studied using chromatography with DEAE-cellulose and Sephadex filtration, electrophoresis, and immunoelectrophoresis. To attribute a renin activity to a tissue or fluid preparation, the substance found should ideally fulfill a combination of (1) biological, (2) physicochemical, (3) inmiunological, and (4) enzymatic criteria on the basis of which its identity with a reference renin may be established.