Amino acid
Definition
The monomer unit of proteins. All 20 standard amino acids share a central carbon bonded to an amino group, a carboxyl group, a hydrogen, and a variable side chain (R-group) that determines the amino acid's chemical properties. Peptide bonds link amino acids end-to-end to form polypeptide chains.
Related terms
- Haemoglobin
- The iron-containing oxygen-transport protein in red blood cells, composed of four polypeptide subunits each with a haem prosthetic group. Its pseudoperoxidase activity...
- Isoenzyme (isozyme)
- Multiple molecular forms of the same enzyme that differ in amino acid sequence but catalyse the same reaction. In forensic serology, isoenzyme...
- Peroxidase
- An enzyme that catalyses the transfer of oxygen from hydrogen peroxide to an electron donor, often producing a coloured product. Haemoglobin has...
- Protein denaturation
- The loss of a protein's three-dimensional structure without breaking peptide bonds, caused by heat, pH change, UV radiation, or chemical agents such...
- Proteolysis
- The hydrolytic cleavage of peptide bonds by proteolytic enzymes (proteases). In biological evidence, proteolysis occurs via endogenous cellular proteases released during autolysis...
Explained in
- Proteins and Enzymes in Biological EvidenceThe monomer unit of proteins. All 20 standard amino acids share a central carbon bonded to an amino group, a carboxyl group, a hydrogen, and a variable side ch...