Bio-Tools

Amino acid Composition Calculator

Protein Parameters Analyzer

Analyze biochemical and physical parameters of your protein sequences

Input Protein Sequence

Only standard amino acid characters are accepted.

0 amino acids
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Analysis Results
Your protein parameters will appear here after analysis.

Authors: Mahdi Morshedi Yekta, Fatemeh Faryadras | Need help? Contact Support

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Our Amino Acid Composition Calculator provides a fundamental analysis of your protein sequence. By simply inputting a sequence, this web-based tool instantly calculates the absolute number and percentage of each of the 20 standard amino acids. This information is the cornerstone of protein characterization, forming the basis for calculating other essential properties like molecular weight and theoretical pI. It is an indispensable tool for researchers verifying protein identity, comparing protein sequences, or designing synthetic genes for recombinant expression.

Amino acid Composition Calculator

How to Use

Analyzing your protein sequence is a simple, three-step process:

  1. Input Sequence: Paste your protein sequence into the text box. The sequence should contain only standard single-letter amino acid codes.
  2. Analyze: Click the “Analyze Sequence” button to process your data.
  3. Review Results: The tool will instantly display a comprehensive report, including a detailed table of the amino acid composition.

Tip: The tool is case-insensitive and ignores whitespace. Ensure your pasted sequence does not contain any non-standard characters (like X, B, Z) for an accurate analysis.

How is the Amino Acid Composition Calculated?

The calculation of amino acid composition is a direct and straightforward process. The algorithm performs the following steps:

  1. Count Residues: The tool iterates through the input protein sequence, one amino acid at a time, and maintains a separate counter for each of the 20 standard amino acids. It tallies the occurrences of each specific residue.
  2. Calculate Total: The total number of amino acids is determined, which is equivalent to the length of the sequence.
  3. Determine Percentages: The percentage for each amino acid is then calculated by dividing its individual count by the total number of amino acids and multiplying the result by 100.

The final output is a clear table listing the absolute count and relative frequency (percentage) for every amino acid present in the protein.

Features and Outputs

This protein parameters analyzer provides the following comprehensive outputs:

  • Amino Acid Composition: Delivers the absolute count and percentage frequency for each of the 20 standard amino acids in your sequence.
  • Molecular Weight (MW): Calculates the protein’s molecular weight based on its amino acid composition.
  • Theoretical Isoelectric Point (pI): Estimates the pH at which the protein carries no net electrical charge.
  • Instability Index: Computes a score to predict the protein’s stability in a test tube.
  • Estimated Half-Life: Predicts the protein’s in vivo stability in different biological systems.
  • Amino Acid Property Groups: Classifies and sums amino acids based on their chemical properties (e.g., Hydrophobic, Polar, Positively Charged, Negatively Charged).
  • Atomic Composition: Provides the total count of each atom type (Carbon, Hydrogen, Nitrogen, Oxygen, Sulfur) that makes up the protein molecule.
  • Extinction Coefficient: Estimates the molar absorption coefficient, essential for determining protein concentration.
  • Aliphatic Index: Calculates the relative volume occupied by aliphatic side chains, a positive indicator of thermostability.
  • Grand Average of Hydropathicity (GRAVY): A score representing the overall hydrophobicity of the protein.

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FAQ

References & Suggested Reading

This tool was developed in line with established principles in computational biochemistry for accurate, reliable results. The resources listed below are the foundational research and key papers that define these standards, and we highly recommend them for a deeper understanding of the scientific principles.

  1. Nelson, D. L., & Cox, M. M. (2021). Lehninger Principles of Biochemistry (8th ed.). Macmillan Learning. (Chapter 3: Amino Acids, Peptides, and Proteins provides a comprehensive background on this topic).
  2. Gasteiger, E., Hoogland, C., Gattiker, A., Duvaud, S., Wilkins, M. R., Appel, R. D., & Bairoch, A. (2005). Protein identification and analysis tools on the ExPASy server. In J. M. Walker (Ed.), The Proteomics Protocols Handbook (pp. 571–607). Humana Press. https://doi.org/10.1385/1-59259-890-0:571

Meet the Authors

Mahdi Morshedi Yekta

Mahdi Morshedi Yekta

Founder & Bioinformatics Developer

Mahdi is the founder of ScienceCodons and a Medical Biotechnologist with a deep passion for computational biology. Holding an M.Sc. in Medical Biotechnology, he specializes in transforming complex biological algorithms into accessible, high-performance web tools, bridging the gap between laboratory sciences and software engineering.

Fatemeh Faryadras

Fatemeh Faryadras

Medical Biotechnologist & Researcher

Fatemeh is a Medical Biotechnologist and researcher. With extensive expertise in genetic engineering, molecular cloning, and cancer biology, she combines her rigorous laboratory background with intuitive design principles to create reliable, user-centered scientific calculators and tools.