Protein Average Mass
Sum average isotopic residue masses plus terminal water for a protein sequence.
Description
Average isotopic protein mass sums average residue masses and terminal water.
Average isotopic protein mass sums average residue masses and terminal water. It differs from a monoisotopic mass calculation.1
Sum average isotopic residue masses plus terminal water for a protein sequence.
When to use Protein Average Mass
Use this tool to sum average isotopic residue masses plus terminal water for a protein 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 Protein Average 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, waterMassDa using the field table and calculation rules, then run the tool.
- Read averageMassDa, residueCount. 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 |
| waterMassDa | Water mass da | number | Required |
Enter a canonical sequence and positive terminal water mass in daltons. Return total average mass and canonical residue count.
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.
averageMassDa=ΣaverageResidueMass+waterMassDa Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| averageMassDa | Average mass da | number |
| residueCount | Residue count | number |
{
"input": {
"sequence": "A",
"waterMassDa": 18.01528
},
"output": {
"averageMassDa": 89.09408,
"residueCount": 1
}
}Limitations and assumptions
The tool assumes one unmodified chain and uses its committed residue table. Isotope-specific masses, disulfides and modifications are not added.
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 Peptide Neutral Mass: Calculate monoisotopic neutral peptide mass from its canonical sequence. For a complementary task, use Protein Elemental Formula: Sum C/H/N/O/S protein elemental formula from residue compositions and termini.
References
-
Protein Average Mass — tool.io
Similar or alternative tools
- Peptide Neutral Mass
Calculate monoisotopic neutral peptide mass from its canonical sequence.
- Protein Elemental Formula
Sum C/H/N/O/S protein elemental formula from residue compositions and termini.