QUIZ 2 APKLAB

Role of Enzyme regarding chemical reactions

Activation energy

the energy necessary for reaction

energy released remains the same, only change activating energy barrier

Describe factors influencing reaction rates

1. Reactant and Product Concentrations

2. Temperature

3. Height of Activation Energy Barrier

Shorter the height of the activation barrier,

Describe factors influencing enzymatic rates

Temperature

◼ pH

◼ Cofactors and coenzymes

◼ Concentration of enzyme and substrate

▫ Saturation

◼ Affinity

Optimal temperature for chemical reactions

37 DEGrees celcius,

Optimal pH depends on location

Describe factors influencing enzyme regulation

The body regulates the activity of enzymes to

adjust the rates of reactions in response to

changing demands…

Methods for altering enzyme activity:

◼ Allosteric Regulation

◼ Covalent Regulation

◼ Feedback Inhibition (end product inhibition)

Allosteric Regulation

modulator binds to regulator site, alters activity (+ or -)

The allosteric inhibitor (modulator) binds to the enzyme, but at a location other than the active sit

Covalent Regulation

active site are altered due to covalent modification of structure

Describe how temperature and pH influence enzyme, ‘Lactate Dehydrogenase’

Higher concentrations (saturation) of substrate or enzyme result in

faster reaction rate

A plateau occurs when there is more enzyme than substrate to the point where no more can fit.

affinity = stronger bond between substrate and enzyme = quicker reaction

Feedback Inhibition

Metabolic control that ‘product’ acts as an inhibitor of a specific enzyme within that metabolic pathway

The inhibited enzyme is often the rate-limiting enzyme

always the one before stopping the chain