Calculate the molecular weight of any protein from its amino acid sequence. Results in Da and kDa with full residue composition.
Accepted: single-letter IUPAC codes (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y). FASTA headers and spaces are ignored automatically.
Each disulfide bond reduces MW by 2.016 Da (loss of 2H).
Protein molecular weight (MW) is the sum of the molecular weights of all amino acid residues in the sequence, plus one water molecule (18.02 Da) for the free N- and C-termini.
Each amino acid has a unique residue mass (the mass after losing water during peptide bond formation). These residue masses, as defined by NIST and used in proteomics databases, are used in this calculator.
Results are given in Daltons (Da) and kiloDaltons (kDa). For most recombinant proteins expressed in E. coli or mammalian cells, the molecular weight ranges from 10 kDa to 200 kDa.
Note: This calculator uses monoisotopic residue masses based on average atomic weights. Post-translational modifications (glycosylation, phosphorylation, etc.) are not included.
The following average residue masses (Da) are used for calculation:
A=71.08, R=156.19, N=114.10, D=115.09, C=103.14, E=129.12, Q=128.13, G=57.05, H=137.14, I=113.16, L=113.16, K=128.17, M=131.20, F=147.18, P=97.12, S=87.08, T=101.10, W=186.21, Y=163.18, V=99.13