Amino Acid Composition
Tabulate amino-acid counts and composition percentages.
Description
Amino-acid composition tabulates the residue types observed in a sequence.
Amino-acid composition tabulates the residue types observed in a sequence. Percentages describe overall composition without retaining positional order.1
Tabulate amino-acid counts and composition percentages.
When to use Amino Acid Composition
Use this tool to tabulate amino-acid counts and composition percentages.
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 Amino Acid Composition 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 residueSymbols, counts, percentages. 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. Return only observed residue symbols sorted alphabetically, with aligned counts and percentages. Unobserved types are omitted rather than returned as zero rows.
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.
percentage(residue)=100 count(residue)/sequenceLength Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| residueSymbols | Residue symbols | list of string |
| counts | Counts | list of number |
| percentages | Percentages | list of number |
{
"input": {
"sequence": "AA"
},
"output": {
"residueSymbols": [
"A"
],
"counts": [
2
],
"percentages": [
100
]
}
}Limitations and assumptions
The table does not identify sequence motifs, modifications, structure or biological function.
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 Aromaticity: Calculate aromatic F/W/Y residue fraction of a protein sequence. For a complementary task, use Protein Aliphatic Index: Calculate protein aliphatic index from Ala, Val, Ile, and Leu fractions.
References
-
Amino Acid Composition — tool.io
Similar or alternative tools
- Protein Aromaticity
Calculate aromatic F/W/Y residue fraction of a protein sequence.
- Protein Aliphatic Index
Calculate protein aliphatic index from Ala, Val, Ile, and Leu fractions.