BRAINCAKEConjugated Proteins
A conjugated protein is a protein that is permanently joined to a non-protein component. The non-protein part is called a prosthetic group. The protein part on its own usually cannot do its job; the prosthetic group is essential for the protein's function.
The best-known example is haemoglobin, the oxygen-carrying protein in red blood cells. Haemoglobin is a globular protein with a quaternary structure made of four polypeptide chains: two α-globin chains and two β-globin chains. Each chain is folded around a haem group, the prosthetic group. Every haem group contains an iron ion (Fe2+), and each iron ion can bind one oxygen molecule reversibly.
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Key terms in this lesson
- haemoglobin
- A globular, conjugated protein in red blood cells made of four polypeptide chains, each with a haem prosthetic group, that transports oxygen.
More in Biological Molecules
- Amino-acids
- Hydrogen Bonding
- Disulfide Bridges
- Ionic Bonds
- Protein Structure
- Globular Proteins
- Fibrous Proteins
- Collagen
All 25 lessons in Biological Molecules · All Edexcel AS-level Biology topics