Explore amino acid composition for research or bioinformatics. Instantly summarize residue frequencies with visual tables. Designed for chemists, biochemists, students, and laboratory professionals everywhere.
Use these small sequences to test the calculator quickly. Copy a sequence into the input area and press Calculate composition.
| Example name | Description | Sequence |
|---|---|---|
| Balanced test peptide | Includes one copy of each standard amino acid. | ACDEFGHIKLMNPQRSTVWY |
| Positively charged fragment | Enriched in lysine and arginine to test charge bias. | AKKRQKRRKAKR |
| Acidic fragment | Rich in aspartate and glutamate residues. | DEDEDDDEEEDE |
The calculator counts how many times each amino acid appears in the cleaned sequence. Mole percentage is calculated as:
Mole % = (count of residue / total valid residues) × 100
Estimated mass percentage uses approximate residue masses. For each residue type, mass contribution equals count multiplied by residue mass. Mass % is that contribution divided by the sum over all residue types, multiplied by 100.
Amino acid composition describes how often each residue appears within a protein or peptide sequence. Instead of examining individual positions, you look at overall counts and percentages. This overview reveals structural tendencies, hydrophobicity balance, and charge distribution, which are crucial when comparing proteins, designing constructs, or interpreting experimental data.
In practical chemistry and biochemistry, composition profiles guide many routine decisions. Enrichment in acidic residues affects solubility and buffer interactions, while hydrophobic residues hint at membrane association. When you compare two proteins, similar profiles often indicate related structure or function, even before you run detailed structural analysis or advanced simulations.
This calculator expects sequences expressed using the twenty standard one-letter amino acid codes. You can paste sequences directly from FASTA files; the tool automatically strips whitespace and line breaks. Non-standard characters are reported so you can clean experimental data, but an option lets you ignore them when screening many sequences quickly.
For each residue type, the calculator counts occurrences and divides by the total number of valid residues to obtain mole percentage. To estimate mass contribution, it multiplies counts by typical residue masses and normalizes by the total. For solution design, combine these values with a dedicated molarity calculator for precise concentration planning.
Start by pasting your sequence into the input area. Choose whether to ignore non-standard characters and select a sorting mode for the table. Press Calculate to generate results. You can then download the composition as CSV for spreadsheets or as a lightweight PDF summary for quick reporting or documentation.
The results table summarizes counts, mole percentages, and approximate mass contributions for each amino acid. High lysine or arginine content suggests strong positive charge at physiological pH, while aspartate and glutamate increase negative charge. Noting extremes in hydrophobic or aromatic residues helps anticipate aggregation, binding behavior, or chromatography performance during purification workflows.
When planning stock solutions, composition informs how much peptide mass you need for a target molar concentration. After obtaining the total molecular mass, you can switch to tools such as the mass dilution calculator to convert between grams, moles, and final working volumes accurately.
In everyday laboratory work, composition checks are valuable quality-control steps. You might verify that an expressed protein matches the expected design or compare theoretical calculations with mass-spectrometry data. Combined with resources like a cylinder mass calculator for precise solvent handling, this tool supports more consistent, reproducible preparation of biochemical reagents.
It takes a protein or peptide sequence, counts each residue type, and returns a table with counts, mole percentages, and approximate mass contributions together with overall sequence length and estimated molecular mass.
Enter sequences using standard one-letter amino acid codes. You may paste raw sequences or FASTA records; the header line is ignored if present, and whitespace characters are automatically removed before composition is calculated.
Mass values use typical average residue masses and therefore provide approximate totals. For high-precision work, confirm results with specialized mass-spectrometry software or vendor tools, especially when post-translational modifications or non-standard residues are involved.
Yes. Analyze one sequence at a time, then download each result as CSV. You can merge multiple CSV files in a spreadsheet to compare composition profiles across variants, mutants, or constructs from different expression experiments.
Once you know the molecular mass, you can switch to tools like the site’s molarity calculator to translate required moles into grams for stock solutions at specific volumes and target concentrations.
Many sequence files include symbols for stop codons, tags, or unknown residues. The calculator reports these characters and, if ignoring them is selected, excludes them from totals so your composition focuses only on the twenty standard amino acids.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.