Protein Sequence Residue Count Length Calculator
Count validated canonical amino-acid residues, not FASTA headers, terminators or ambiguous residue assignments.
Description
Count validated canonical amino-acid residues, not FASTA headers, terminators or ambiguous residue assignments.
Residue count measures the length of a normalized protein sequence. It counts amino-acid symbols rather than bytes, words or an inferred molecular mass.
When to use this tool
Count validated canonical amino-acid residues, not FASTA headers, terminators or ambiguous residue assignments.
- 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.residueCount. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Normalize the input through the shared protein-sequence helper and return its length as residueCount.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.residueCount | The residue count value under the stated formula or text convention. |
{
"input": {
"sequence": "ACDE"
},
"output": {
"result": {
"residueCount": 4
}
}
}Limitations and assumptions
- Only the supported canonical residue alphabet is accepted after trimming leading/trailing whitespace and uppercase conversion. FASTA headers, stop symbols and ambiguous residues are not interpreted as sequence records.
- 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
- protein sequence coverage
Sequence coverage is the union of supplied peptide intervals on a protein.
- protein sequence isoelectric point
Sequence isoelectric pH is a modeled pH where net charge approaches zero.