AGT and blood pressure trait: There are two different mechanisms for lowering blood pressure: following the renin–angiotensin system (RAS), the enzyme renin catalyzes the conversion of angiotensinogen to angiotensin I. Following a cascade reaction, the angiotensin-converting enzyme (ACE) subsequently converts angiotensin I to angiotensin II which is a vasoconstrictor agent that will ultimately generate an increased high blood pressure.