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What is the difference between an accession number (AC) and the entry name?

Last modified April 23, 2007

An accession number (AC) is assigned to each sequence upon inclusion into UniProtKB. Accession numbers are stable from release to release. If several UniProtKB entries are merged into one, for reasons of minimizing redundancy, the accession numbers of all relevant entries are kept. Each entry has one primary AC and optional secondary ACs.

The 'Entry name' (formerly ID) is a unique identifier, often containing biologically relevant information. It is sometimes necessary, for reasons of consistency, to change IDs (for example to ensure that related entries have similar names). Another common cause for changing an ID is when an entry is promoted from UniProtKB's TrEMBL section (with computationally-annotated records) to the Swiss-Prot section (with fully curated records). However, an accession number (AC) is always conserved, and therefore allows unambiguous citation of UniProt entries. If a UniProtKB entry contains more than one accession number, the first one (or primary accession number) should be cited.