Peptide Neutral Mass

Calculate monoisotopic neutral peptide mass from its canonical sequence.

Description

Monoisotopic neutral peptide mass adds residue masses and one terminal water molecule.

Monoisotopic neutral peptide mass adds residue masses and one terminal water molecule. It excludes charge-carrying protons.^[1]

Calculate monoisotopic neutral peptide mass from its canonical sequence.

When to use Peptide Neutral Mass

Use this tool to calculate monoisotopic neutral peptide mass from its canonical sequence.

Prepare the canonical sequence, peptide assignments, fitted assay parameters or upstream measurements requested. Keep corresponding entries aligned, use the stated mass and signal units, and remove FASTA headers before entering sequence text.

How to use Peptide Neutral Mass and understand its results

Prepare the canonical sequence, peptide assignments, fitted assay parameters or upstream measurements requested. Keep corresponding entries aligned, use the stated mass and signal units, and remove FASTA headers before entering sequence text.
Enter sequence using the field table and calculation rules, then run the tool.
Read neutralMassDa. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
sequence	Sequence	string	Required

Enter a canonical sequence. Sum the committed residue mass table starting with 18.01056 Da and return neutral mass.

The shared sequence helper trims outer whitespace and uppercases the sequence. It requires at least one residue from ACDEFGHIKLMNPQRSTVWY. Internal whitespace, FASTA headers, ambiguous letters and modified-residue notation are rejected. Sequence indexes refer to the normalized sequence; individual tools may preserve original strings in their returned lists as explained above.

neutralMassDa=ΣmonoisotopicResidueMass+18.01056

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
neutralMassDa	Neutral mass da	number

json

{
  "input": {
    "sequence": "A"
  },
  "output": {
    "neutralMassDa": 89.04767
  }
}

Limitations and assumptions

This assumes an unmodified reduced chain. Disulfides, isotope labels, terminal modifications and protonation are not included.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Protein Average Mass: Sum average isotopic residue masses plus terminal water for a protein sequence. For a complementary task, use Precursor MZ: Calculate peptide precursor m/z for a given integer charge.

References

Peptide Neutral Mass — tool.io

Similar or alternative tools

Protein Average Mass
Sum average isotopic residue masses plus terminal water for a protein sequence.
Precursor MZ
Calculate peptide precursor m/z for a given integer charge.