PEPlife2: An Updated Repository of the Half-Life of Peptides and Proteins

This manuscript presents an updated version of PEPlife, a manually curated database that provides extensive information on peptide half-life. The updated version, PEPlife2, contains 4500 total entries, including 2300 newly curated entries and 2200 entries from the previous PEPlife database. These entries correspond to 1673 unique peptide sequences and 257 unique protein sequences where different entries may refer to the same peptide/protein sequence, the half-life of which was evaluated using different experimental assays. Each entry contains detailed information, including experimental methods used to determine half-life, chemical modifications, biological activity, routes of administration, and other relevant data. In addition to unmodified peptide sequences, PEPlife2 includes cyclic peptides and chemically modified peptides, such as those with N- and C-terminal modifications. To provide structural insights, peptide and protein structures were sourced from the Protein Data Bank (PDB) or predicted using PEPstrMOD. PEPlife2 integrates advanced analytical tools including BLAST (version 2.7.1), Smith–Waterman and CLUSTALW. This database provides a valuable resource for peptide and protein therapeutics research, particularly in the design of immunotherapeutics and vaccines.