Concept:Zymogens require specific environmental conditions or chemical triggers to cleave their inhibitory peptide bonds and become active.
Formula:N/A
Solution:- In the stomach, parietal cells secrete a highly concentrated solution of Hydrochloric acid (HCl).
- This extreme acidity (pH ~2) causes a conformational change in the pepsinogen molecule, allowing it to auto-cleave a small peptide fragment from itself.
- This cleavage uncovers the active site, converting the inactive pepsinogen into the active protease pepsin.
Why other options are incorrect:While active pepsin can activate more pepsinogen (autocatalysis), the initial and primary converter is the highly acidic HCl environment. Hormones (like gastrin) stimulate secretion but do not directly activate the enzyme chemically.
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