|
|
| (12 intermediate revisions by the same user not shown) |
| Line 1: |
Line 1: |
| The term ''chain'', in biochemistry, usually denotes either a polypeptide chain or a polynucleotide chain. A polypeptide chain is a sequence of [[amino acids]] covalently linked by [[peptide bonds]]. A short polypeptide consisting of 50 or fewer amino acids is termed a [[peptide]]. A polynucleotide chain is a sequence of [[standard residues|nucleotides]] covalently linked by ribose (or deoxyribose)-phosphate bonds, e.g. either [[DNA]] or [[RNA]].
| | #REDIRECT [[Chains and Chain IDs]] |
| | |
| Polypeptide ([[protein]]) chains are linear, with rare exceptions where a side-chain forms a peptide bond (example needed). Polypeptide chains may be covalently linked together, most commonly by disulfide bonds.
| |
| | |
| Protein molecules may consist of one or more polypeptide chains, homo-oligomers or hetero-oligomers, homo-multimers or hetero-multimers. The functional form of the molecule, termed the [[biological unit]], often contains a different number of chains than does the crystallographic [[asymmetric unit]]. Examples are given in the article on [[biological units]].
| |