Renin
Aspartyl protease enzyme that cleaves angiotensinogen to angiotensin I, initiating the renin-angiotensin-aldosterone system.
Chemical Identity
| Property | Value |
|---|---|
| Molecular Weight | ~37 kDa (active renin) |
| Gene | REN |
| Enzyme Class | Aspartyl Protease (EC 3.4.23.15) |
| Substrate | Angiotensinogen |
| Product | Angiotensin I (decapeptide) |
Structure
Renin is an aspartyl protease produced as preprorenin (406 amino acids) and processed to active renin (340 amino acids). It contains two aspartate residues in the active site essential for catalysis. Renin is synthesized and stored in juxtaglomerular cells of the kidney afferent arteriole.
Mechanism of Action
Renin cleaves the Leu10-Val11 bond of angiotensinogen (produced by the liver) to release angiotensin I, a decapeptide with no biological activity. This is the rate-limiting step of the RAAS cascade. ACE then converts Ang I to the active octapeptide Ang II. Renin secretion is regulated by renal perfusion pressure, sympathetic nervous system, and negative feedback.
Clinical Applications
- RAAS initiation: Rate-limiting enzyme in blood pressure regulation
- Aliskiren: Direct renin inhibitor for hypertension
- Renin assays: Plasma renin activity for hypertension diagnosis
- Reninomas: Rare renin-secreting tumors causing hypertension
Pharmacology
- Half-life: 80-120 minutes (active renin)
- Regulation: Increased by low renal perfusion, sympathetic activation, decreased by Ang II feedback
- Specificity: Highly specific for angiotensinogen
- Tissue renin: Local RAAS in heart, brain, vasculature
References
- Skeggs, L.T., et al. (1957). The preparation and function of the hypertensin-converting enzyme. Journal of Experimental Medicine, 103, 295-299.
- Fisher, N.D.L., & Hollenberg, N.K. (2001). Renin inhibition: what are the therapeutic opportunities? Journal of the American Society of Nephrology, 12, 2166-2174.
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