ACE converts which of the following?

• A. Angiotensin II to Angiotensin III
• B. Angiotensin I to Angiotensin II
• C. Angiotensin I to Angiotensin III
• D. Bradikinin to Angiotensin I

Answer: (B)

Angiotensin-converting enzyme (ACE) plays a crucial role in the renin-angiotensin-aldosterone system (RAAS), which is important for regulating blood pressure and fluid balance. The primary function of ACE is to convert angiotensin I, an inactive precursor, into angiotensin II, a potent vasoconstrictor with significant physiological effects on blood pressure regulation.

Angiotensin II is not only responsible for vasoconstriction but also stimulates the secretion of aldosterone from the adrenal cortex, which further promotes sodium and water retention, thus increasing blood volume and blood pressure. This conversion is a key step in the RAAS, making it vital for understanding cardiovascular and renal pathophysiology.

The other choices do not accurately represent the primary function of ACE. For example, angiotensin III is a form of angiotensin that has its own production pathway, and bradykinin is a different peptide that is primarily involved in vasodilation and inflammatory responses rather than being converted by ACE.