4.4 Cofactors, coenzymes, prosthetic groups Flashcards
What is a cofactor
Non-protein helper component, helps enzymes carry out its function, binds loosely/temporarily to enzyme to activate them
–> they can transfer atoms or groups from one reaction to another multi-step pathway
What is a coenzyme
organic cofactor
Where are inorganic cofactors found
obtained via diet as minerals
e.g. iron/ calcium, chloride zinc
How are coenzymes obtained
from vitamins (class of organic molecule found in diet)
Prosthetic groups
co factors required by certain enzymes to carry out catalytic function
–> tightly bound and form a permanent feature of protein
Zinc Ions form an important part in the structure of which enzyme?
Carbonic Anhydrase, necessary for the metabolism of Carbon Dioxide
Inactive precursor enzymes
Enzymes that are produced in an inactive form
Why are some enzymes produced as inactive?
Some enzymes can cause damage within the cells or tissue they are produced or released from or some enzymes’ actions need to be controlled or activated under certain conditions
How are Precursor Enzymes activated?
They undergo a shape change in their Tertiary Structure, particularly in their Active Site, which is done by adding a Cofactor
Before the addition of a Cofactor. what is the Precursor Enzyme known as?
Apoenzyme
After the addition of a Cofactor and the Precursor Enzyme is activated, what is the new name of the Precursor Enzyme?
Holoenzyme
How else is the change in the Tertiary Structure achieved in Precursor Enzymes?
The action of another enzyme such as Protease
What two factors can also change the Tertiary Structure of a Precursor Enzyme, creating Zymogens/Proenzymes?
pH and Temperature
What happens when Inactive Pepsinogen is released into the Stomach to digest Proteins?
The acid pH brings about the transformation into the active enzyme pepsin, which protects the body tissues against the digestive action of Pepsin
