Protein Atomic Composition C-H-N-O-S Count Table Builder
Sum polymer residue CHNOS compositions plus terminal H2O for a linear unmodified neutral protein chain; excludes disulfides, modifications and adducts.
Description
Sum polymer residue CHNOS compositions plus terminal H2O for a linear unmodified neutral protein chain; excludes disulfides, modifications and adducts.
An elemental composition model sums residue formulas and the terminal groups of a chain. Explicit terminal-water accounting distinguishes a linear peptide from an unconnected list of free amino acids.
When to use this tool
Sum polymer residue CHNOS compositions plus terminal H2O for a linear unmodified neutral protein chain; excludes disulfides, modifications and adducts.
- Prepare the supplied sequence fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter sequence. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.elements, result.counts, result.assumption. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Normalize the canonical protein sequence, sum the fixed per-residue C/H/N/O/S count vectors, then add H2O once for the chain termini. Return the element order, aligned counts and the linear-unmodified-neutral-chain assumption.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| sequence | sequence. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.elements | The elements list in the ordering and representation described above. |
| result.counts | The counts list in the ordering and representation described above. |
| result.assumption | The assumption value under the stated formula or text convention. |
{
"input": {
"sequence": "AG"
},
"output": {
"result": {
"elements": [
"C",
"H",
"N",
"O",
"S"
],
"counts": [
5,
10,
2,
3,
0
],
"assumption": "linear-unmodified-neutral-chain-with-terminal-water"
}
}
}Limitations and assumptions
- The model omits post-translational modifications, disulfide hydrogen changes, adducts and isotope composition. It does not calculate charge, mass or the composition of noncanonical residues.
- Protein inputs are trimmed at their ends and uppercased; internal whitespace is not removed. Only the twenty canonical amino-acid letters are accepted, with no FASTA header, ambiguity code or stop symbol.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
Use compatible mass, charge and sequence conventions when combining these operations. Inspect experimental spectra or quantitative controls separately; sequence features and theoretical mass arithmetic are not peptide identification or biological interpretation.
References
Similar or alternative tools
- amino acid composition
Amino-acid composition tabulates the residue types observed in a sequence.
- Protein Abundance Z-Score Row Normalizer
Normalize a supplied protein abundance row with sample standard deviation (n−1); constant rows are undefined rather than fabricated zeros.