Enzyme kinetics in lipase hydrolysis

Steps:

• Lipase hydrolyzes lipids into fatty acids, which lower pH; rate is fastest initially with high substrate concentration.
• As reaction proceeds, substrate decreases, slowing the rate and reducing product formation per unit time (statement 1).
• Initial high rate causes rapid pH drop in early minutes (statement 2).
• Later, slower rate leads to less rapid pH change (statement 3).
• Constant pH implies buffering, but recorded changes reflect acid production rate, supporting all statements.

Why A is correct:

• Michaelis-Menten kinetics predicts initial rapid reaction followed by deceleration as substrate depletes, aligning with all three observations.

Why the others are wrong:

• B omits statement 3, but slowing after initial phase is expected.
• C omits statement 2, but rapid early pH change occurs due to high initial rate.
• D omits statement 1, but decreasing substrate limits product formation over time.

Final answer: A