Chain

This subsection of the ‘Sequence annotation (Features)’ section describes the extent of a polypeptide chain in the mature protein following processing.

The processing events that may contribute to the formation of a mature chain are described in the ‘Initiator methionine’, ‘Propeptide’, ‘Signal’ and ‘Transit peptide’ subsections.

The ‘description’ field of the ‘chain’ corresponds to the recommended name listed in the ‘Protein names’ section.
Example: Q6UB98

When several chains are produced from the same precursor, each chain is described in this subsection and is also listed in the ‘Names and origin’ section, ‘Protein name’ subsection, as “Cleaved into the following x chains:”, where ‘x’ represents the number of chains described in the ‘sequence annotation’ section. In both sections, the chains are listed in their order of appearance in the sequence, i.e. from the N- to the C-terminus.
Example: P07683, ‘Sequence annotation’ and P07683, ‘Names and origin’

Each chain has a stable identifier.

See also the ‘Peptide’ subsection which describes small active peptides.