Cofactor, Coenzymes, And Prosthetic Groups Flashcards
what is a cofactor?
a non-protein helper component to help enzymes carry out their function. they transfer atoms or groups from one reaction to another in a multi-steppathway or theymay form part of the active site of an enzyme.
what is a coenzyme?
a cofactor which is an organic molecule.
how are inorganic cofactors obtained?
through the diet via minerals.
which enzyme has an inorganic cofactor
amylase - contains a chloride ion which is necessary for the formation of a correctly shaped active site.
how are organic coenzymes obtained?
derived from vitamins
what is an example of a coenzyme?
NAD - synthesised from vitamin B3. NAD is a coenzyme responsible for th transfer of hydrogen ions between molecules involved in respiration.
what is the role of coenzyme A?
essential in the breakdown of fatty acids and carbohydrates in respiration.
what is the role of prosthetic groups in enzymes?
required by certain enzymes to carry out their catalytic function.
what is the difference between prosthetic groups and coenzymes?
prosthetic groups are tightly bound and form a permanent feature of the protein whereas cofactors and coenzymes bind loosely to proteins in order to activate them.
what are inactive precursor enzymes?
enzymes that are produced in an inactive form.
why do inactive precursor enzymes exist?
- enzymes that can cause damage within the cells producing them
- enzymes whose action needs to be controlled and only activated under certain conditions.
what is a precursor enzyme called before the cofactor is added?
apoenzyme.
what is a precursor enzyme called when the cofactor is added and the enzyme is activated?
holoenzyme
what must precursor enzymes do to be activated?
undergo a change in shape.
what is factor X?
an enzyme that is dependent on the cofactor vitamin K for activation.
