PepCalc Peptide Properties
Calculate physicochemical properties for a peptide with optional N-terminal and C-terminal chemical modifications, using the Pep-Calc.com API. Returns the molecular formula, monoisotopic and average molecular weight, isoelectric point (pI), and 280 nm extinction coefficient (oxidized / reduced cysteine). Unlike a bare-sequence calculator (e.g. ProtParam_calculate, which only accepts standard amino acids with free termini), this tool models the terminal group, so it covers synthetic / therapeut…
Overview
Calculate physicochemical properties for a peptide with optional N-terminal and C-terminal chemical modifications, using the Pep-Calc.com API. Returns the molecular formula, monoisotopic and average molecular weight, isoelectric point (pI), and 280 nm extinction coefficient (oxidized / reduced cysteine). Unlike a bare-sequence calculator (e.g. ProtParam_calculate, which only accepts standard amino acids with free termini), this tool models the terminal group, so it covers synthetic / therapeutic peptides. The terminal group changes the formula, mass, and pI: for example seq=ACDEFGHIK with C_term=NH2 (amide) gives pI 6.96 and MW 1017.47, while C_term=OH (free acid) gives pI 5.23 and MW 1018.45. N_term / C_term are chemical-group strings understood by Pep-Calc: N_term defaults to 'H' (free amine; 'Ac' for N-terminal acetyl), C_term defaults to 'OH' (free acid; 'NH2' for C-terminal amide). No API key required.
Schema
JSON Schema the agent (or your API call) must match.
View JSON schemaExpandCollapse
Examples (1)
Default PepCalc Peptide Properties call
Public-safe example · rate-limited
Identifiers
- Catalog ID
- tu_PepCalc_peptide_properties
- Tool name
- PepCalc_peptide_properties
- Added
- 2026-07-29 18:13Z
- Tags
- tooluniverse