Scientific lookup tool Peptide Sequence Database

Educational resource

How to use this database

Peptide Sequence Database is a scientific lookup tool. Use the Compounds directory to find records, open a compound page for standardized fields, and use these educational guides when a notation or mass convention is unclear. This site is not a storefront and does not provide prescribing advice.

Search

The header search control and the Compounds search box accept:

  • a sequence fragment (for example CYIQNC)
  • a compound name or synonym
  • a CAS Registry Number
  • a PubChem CID

Matching ignores capitalization, spaces, and hyphens. Prefer 1-letter fragments for sequence search. If a peptide is heavily modified, try a distinctive core stretch plus a modification filter rather than the full display string.

Filters

  • Molecular weight — inclusive range in g·mol−1 using the stored average mass
  • Length — residue count as curated on the record
  • Classification — linear or cyclic covalent topology
  • Modifications — select one or more tags; a record must include all selected tags (AND logic)

Combine filters narrowly first (for example cyclic + amidated + length 8–12), then relax constraints if the result set is empty.

Reading a compound record

A typical record includes:

  • name, synonyms, classification, and modification tags
  • 1-letter sequence and display notation
  • length, molecular formula, and molecular weight
  • CAS number and PubChem CID with outbound links
  • structure notes and primary-source references when curated

Use display notation and modifications to interpret chemistry that the 1-letter field cannot show. Use PubChem and CAS Common Chemistry to verify identity independently.

Suggested workflow

  1. Search by name or a short sequence motif.
  2. Confirm the hit with CAS / PubChem.
  3. Compare length, formula, and MW against your expectations using the molecular-weight guide.
  4. Open related Learn pages if termini or rings are unfamiliar.

What this is not

It is not a prescribing reference, not a vendor catalog, not a certificate of analysis, and not a substitute for primary literature. Cross-check sequence, mass, and registry identifiers before laboratory or regulatory use. For research materials and supplier documentation, browse the Nulife catalog.