2.5 enzymes Flashcards
enzyme
a globular protein which acts as a biological catalyst by speeding up the rate of a chemical reaction
why are enzymes able to be reused?
Enzymes are not changed or consumed by the reactions they catalyse
substrate
the molecules the enzyme reacts with
active site
the region on the surface of the enzyme which binds to the substrate molecule
where do enzyme reactions typically occur?
in aqueous solutions
catalase
an enzyme found in the blood, and in most living cells, that catalyses the decomposition of hydrogen peroxide into water and oxygen.
denaturation
a structural change in a protein that alters its three-dimensional shape and causes the loss of its biological properties.
enzyme activity
a measure of the ability of an enzyme to catalyse a specific reaction.
hydrolysis
decomposition of a chemical compound by reaction with water.
lactase
the enzyme responsible for catalysing the split of lactose into galactose and glucose.
lactose
a disaccharide (C12H22O11) found in milk that may be hydrolysed to yield glucose and galactose.
membrane-bound
when an enzyme is fixed in its position
describe enzyme catalysis
- first requires that the substrate has close physical proximity with the active site
- When a substrate binds to the enzyme’s active site, an enzyme-substrate complex is formed
- the enzyme catalyses the conversion of the substrate into product, creating an enzyme-product complex
- The enzyme and product then dissociate – as the enzyme was not consumed, it can continue to catalyse further reactions
what does increasing the rate of enzyme catalysis accomplish?
improves the frequency of collisions b/w substrate and enzyme
2 ways to increase rate of enzyme catalysis
- Increasing the molecular motion of the particles (thermal energy)
- Increasing the concentration of particles (either substrate or enzyme concentrations)
how does denaturation affect the enzyme?
negatively affect the enzyme’s capacity to bind the substrate
what factors influence the rate of activity of an enzyme
Temperature, pH and substrate concentration