Data Source format:

Data Source Format
RefSeq NP_ or XP_, then integers
UniProtKB Starts with a letter, then letters or integers
GeneID Integer
PIR Letter, 4 numbers
Mim Integer
Ensemble ENSG, then integers
UniGene Species abbreviation, then integer
IPI IPI, then numbers
UniRef 100 UniRef100_, a letter, then letters or numbers
UniRef 90 UniRef90_, a letter, then letters or numbers
UniRef 50 UniRef50_, a letter, then letters or numbers
UniParc Starts with 'UPI'