Topic 2.5 - Enzymes Flashcards
What is an enzyme ?
It is a protein with catalytic properties due to its power of specific activation
What is the reactant called in an enzyme-catalysed reaction ?
A substrate
Which what region do enzymes catalyse ?
The active site
What is an enzyme’s purpose ?
Reduce the amount of energy needed for a reaction
What makes an enzyme substrate-specific ?
Molecules other than the substrate do not fit in the active site
What is the result of the reaction ?
Products have been created
Why do we immobilise enzymes ?
To restrict movement and for wide use in the industry.
Give and example of immobilising an enzyme
Production of lactose free milk
What are lactase enzymes obtained from ?
Microorganism found in yeast called Kluveromyces lactis.
Give factors that can affect enzyme activity
Temperature, substrate concentration and pH.
What is the difference between and endothermic and an exothermic reaction ?
In an endothermic reaction the energy in the products is more than the energy in the reactants whereas in an exothermic reaction, the energy is less than the energy in the reactants.
What is the enzyme structure like ?
They have a globular shape and a complex 3D structure.
What is a cofactor ?
An additional non protein molecule that is needed by some enzymes to help the reaction.
Give the two types of cofactors
Prostetic group (tightly bound cofactors) and coenzymes (bound and released easily).
What are the two hypothesises for enzyme-substrate complex ?
Lock and key hypothesis (fit is exact)
Induced fit hypothesis (shape can change).
What are inhibitors ?
Chemicals that reduce the rate of enzymic reaction. They are usually specific and work at low concentrations. They block the enzyme without destroying it.
Give example of inhibitors
Drugs or poisons
What are the two types of inhibitors ?
Reversible and Irreversible
What are the two types of reversible inhibitors ?
Competitive = compete with substrate molecules for the active site
Non competitive = not influenced by substrate concentration
How can enzymes be immobilised ? Give three examples
Adsorption = attaching enzymes to a glass surface
Alginate = trapping in alginate gel
Aggregate = bonding together
