Paper 4 · November 2003 · Enzymes
Between pH3 and pH7, disruption of the ionic bonding that maintains catalase's shape is linked to a rising reaction rate, without yet denaturing the enzyme. What effect does this disruption have on the active site over this range?
ASubstrate binding to the active site becomes permanently irreversible, trapping the substrate in place forever
BThe active site becomes completely unable to bind any substrate at all, stopping the reaction
CThe active site becomes more efficient at binding substrate, so more enzyme-substrate (ES) complexes form
DThe active site permanently changes shape and begins binding an entirely different substrate
Explanation
Over this range the active site becomes more efficient at receiving/binding substrate, so more enzyme-substrate (ES) complexes are formed, raising the reaction rate.
Derived from ZIMSEC Biology 9190/4 Paper 4 (Practical Test), November 2003, Q1