3.1.4.2 Enzymes Flashcards
What is an enzyme?
A globular protein that acts as a catalyst
What determines the structure of enzymes?
The structure is a result of the sequence of amino acids
The active site is the functional area of the enzyme that the substrate fits into
The substrate is specific to the enzyme because of the specific shape of the active site
What are the two ways of enzymes working?
Induced fit: proximity of the substrate leads to a change in the enzyme which forms the functional active site, enzyme is malleable
Lock and key: each enzyme has a specific active site that can only be activated by one substrate, enzyme is rigid
What is a competitive inhibitor?
A competitive inhibitor has a complimentary shape to the substrate, thus preventing the substrate to bind.
What affects enzyme activity?
Temperature, pH, enzyme/substrate concentration
What is a non competitive inhibitor?
It attaches themselves to a binding site and alters the shape of the active site so that the substrate and active site are non-complimentary
What happens when an enzyme combines with it’s substrate?
When the enzyme substrate complex is formed, a strain is put on the bonds which lowers the activation energy
What do enzymes do?
Speeds up the rate of a chemical reaction without undergoing permanent changes themselves
They do this by lowering the activation energy
What determines enzymes?
Enzymes are specific and therefore the active site is determines by the tertiary structure which is determined by the primary sequence.
If the tertiary structure is altered then the substrate will not fit the active site.
How does temperature affect an enzyme?
The rise in temperature breaks bonds that hold the shape of the enzyme together, this then causes the active site to change so that the substrate can no longer bind. The enzyme has denatured.
