Enzymes are biological catalysts
that speed up chemical reactions in living cells without undergoing any
permanent change themselves. The molecules that enzymes act on are called substrates,
and each enzyme is usually very specific, catalyzing reactions for
particular substrates to produce specific products.
Structure
and Components of Enzymes:
- Most enzymes are proteins.
- Many enzymes require a non-protein
component, called a cofactor, to function properly. Without it,
the enzyme may be inactive.
Key Terms:
1. Apoenzyme: The inactive protein part of an
enzyme without its cofactor.
2. Holoenzyme: The complete, active enzyme, which
includes the protein and its cofactor.
3. Cofactor: A non-protein component essential
for enzyme activity.
o Coenzyme: If the cofactor is an organic
molecule (e.g., vitamins).
o Metal Ion: Some cofactors are metal ions.
o Prosthetic Group: A cofactor tightly bound to
the enzyme, difficult to remove without damaging the enzyme.
Diagrammatic Summary:
Inactive
Protein (Apoenzyme) + Cofactor (Coenzyme or Metal Ion) → Active Enzyme
(Holoenzyme)
Both
the protein and the cofactor can participate directly in the catalytic
process, ensuring that reactions proceed efficiently and accurately.
No comments:
Post a Comment