Purification and characterization of one-chain and two-chain renins from mouse submandibular gland.

Biosynthetic processing of mouse submandibular gland renin involved sequential proteolytic cleavages of preprorenin to prorenin; the prorenin, in turn, rapidly converted to one-chain and slowly to two-chain renins that were both enzymatically active. One-chain and two-chain renins were purified by an eight-step purification including carboxymethyl cellulose and high performance liquid chromatography (HPLC). The specific activity of the purified one-chain renin was fivefold higher than the two-chain renin. Purified heavy-chain renin was obtained by dithiotreitol incubation of two-chain renin. The heavy chain, isolated by HPLC, retained less than 4% of the activity of the native two-chain, indicating that light-chain renin is essential for enzymatic activity. Previous data indicate that both one-chain and two-chain renins are secreted. One-chain renin is immediately secreted into the media after synthesis, whereas two-chain renin is secreted later. These results suggest that renin may be secreted by two separate pathways--an early pathway from the golgi and another pathway from the secretory granules. Our data indicate that renin biosynthesis and secretion are complex and may be controlled at multiple points.

Duke Scholars

Author Victor J. Dzau Medicine, Cardiology