loretopaulinojr
commented
8 months ago Cofactors and Prosthetic Groups
Cofactors:
Definition: Cofactors are small, inorganic, or organic molecules that are loosely bound to the enzyme. They can be metal ions (inorganic cofactors) or organic molecules (organic cofactors or coenzymes).
Binding: Cofactors are not tightly bound to the enzyme's structure and can be easily dissociated from the enzyme.
Role: Cofactors participate in catalysis by providing chemical groups that the enzyme cannot provide on its own. They may assist in substrate binding, transfer functional groups, or participate in redox reactions.
Examples: Metal ions like Mg²⁺ and Zn²⁺ are inorganic cofactors. Coenzymes like NAD⁺, FAD, and coenzyme A (CoA) are organic cofactors.
Prosthetic Groups:
Definition: Prosthetic groups are tightly and permanently attached to the enzyme. They are often organic molecules, but unlike coenzymes, they are not readily released from the enzyme under normal physiological conditions.
Binding: Prosthetic groups are tightly bound to the enzyme's structure and are necessary for the enzyme's function. They are a permanent part of the enzyme's structure.
Role: Prosthetic groups play a crucial role in the catalytic activity of the enzyme. They can participate directly in the catalytic mechanism or assist in stabilizing the enzyme's active conformation.
Examples: Heme in hemoglobin and myoglobin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) in certain dehydrogenases, and biotin in carboxylase enzymes are examples of prosthetic groups.
In summary, the key difference lies in the strength of association with the enzyme: cofactors are loosely bound and can be released, while prosthetic groups are tightly bound and are a permanent part of the enzyme's structure. Both play vital roles in enzyme catalysis and are essential for various biological processes in living organisms.
This a list of vocabulary I stumbled upon and should remember from time to time.