2.2 Enzymes

Enzyme Kinetics Lab

Tweak solution temperature and pH to study lock-and-key substrate fits. Plot rate of reaction graphs to find enzyme optimum peaks and denaturing thresholds.

Virtual Viewport
Lock-and-Key Enzyme Model
✓ ACTIVE
ACTIVE SITEENZYMESSSPPSubstrateProductEnzyme
Rate vs Temperature
RateTemperature (°C)Denatured04080
Live Readings
Activity50%
Collisions/s29
Reactions/s19

Active Sliders

TTemperature37°C
080

Kinetic energy of molecules (peaks at body temp, denatures >50°C).

pHpH Level7.00pH
014

Acidity of solution (optimum 7 for general enzymes).

[S]Substrate Concentration50%
10100

Substrate molecules available for binding.

Syllabus Objectives

  • Explain enzyme action in terms of lock-and-key active site binding
  • Describe effects of temperature and pH changes on enzyme activity
  • Explain denaturation as permanent shape change of active sites.

Mathematical Equations

Enzyme Substrate Complex
E + S ⇌ ES → E + P
Optimal Rate
Rate_{max} \approx f(T_{opt}, pH_{opt})

Inquiry Guide Sheet

1

Set pH to 7. Slowly increase temperature from 10°C to 80°C. Identify optimal temperature (peaks around 37-40°C).

2

Observe the reaction at 60°C. Notice how the active site changes shape (denatures) and activity stops.

3

Vary pH. Observe how highly acidic (pH 2) or basic (pH 12) environments denature the enzyme.