Enzymes and reaction evidence

Enzymes lower activation energy without being consumed overall. In induced fit, substrate binding changes active-site conformation. Temperature, pH and inhibitors can alter activity. Warming often increases rate until instability or denaturation becomes important; there is no universal optimum temperature for every enzyme.

Calculate rate as product increase divided by elapsed time, keeping the stated units. An initial rate uses an early interval before substantial substrate depletion or product build-up. At fixed enzyme concentration, more substrate can increase rate until active sites approach saturation. A plateau is a region where more substrate produces little further rate increase. When sufficient substrate remains, increasing enzyme concentration can increase total catalytic capacity.

Watch out: An enzyme lowers the activation-energy barrier through a suitable reaction pathway.