Analyze biochemical and physical parameters of your protein sequences
Input Protein Sequence
Only standard amino acid characters are accepted.
Was this tool helpful?
Our Atomic Composition Protein Calculator provides a precise elemental breakdown of your protein sequence. By simply inputting a sequence, this tool calculates the exact number of Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), and Sulfur (S) atoms. It presents it as a standard molecular formula. This fundamental data is essential for determining a protein’s precise molecular weight, which is critical for high-resolution mass spectrometry, elemental analysis, and other advanced biochemical applications.
How to Use
Analyzing your protein sequence is a simple, three-step process:
- Input Sequence: Paste your protein sequence into the text box. The sequence should contain only standard single-letter amino acid codes.
- Analyze: Click the “Analyze Sequence” button to process your data.
- Review Results: The tool will instantly display a comprehensive report, including the precise atomic composition and molecular formula of your protein.
Tip: For the most accurate results, ensure your sequence is complete and does not contain any ambiguous or non-standard amino acid characters.
How is the Atomic Composition Calculated?
The calculation of a protein’s atomic composition is based on the summation of the known chemical formulas of its constituent amino acids.
- Summation of Formulas: The tool first determines the amino acid composition (the count of each of the 20 standard amino acids). Since each amino acid has a fixed atomic formula (e.g., Glycine is C₂H₅NO₂), the algorithm multiplies the count of each residue by its respective atomic formula and sums these values together.
- Correction for Peptide Bonds: When amino acids join to form a protein, a molecule of water (H₂O) is lost for each peptide bond created. For a protein with ‘L’ amino acids, there are ‘L-1’ peptide bonds. Therefore, the algorithm subtracts (L-1) hydrogen atoms and (L-1) oxygen atoms from the initial sum.
- Final Formula: The result is the precise atomic composition (C, H, N, O, S) and the overall molecular formula for the entire polypeptide chain.
Features
This protein parameters analyzer provides the following comprehensive outputs:
- Atomic Composition: Provides the total count of each type of atom (Carbon, Hydrogen, Nitrogen, Oxygen, Sulfur) and the protein’s overall molecular formula.
- Molecular Weight (MW): Calculates the protein’s molecular weight based on the average isotopic masses of the atoms in its exact formula.
- Amino Acid Composition: Delivers the absolute count and percentage frequency for each of the 20 standard amino acids.
- 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.
- Extinction Coefficient: Estimates the molar absorption coefficient, essential for determining protein concentration via UV spectroscopy.
- Aliphatic Index: Calculates the relative volume occupied by aliphatic side chains.
- Grand Average of Hydropathicity (GRAVY): A score representing the overall hydrophobicity of the protein.
Support Our Work
We are committed to keeping our scientific tools free and accessible for everyone. If this tool has been helpful in your work, please consider supporting our mission with a donation. Your support directly helps us cover server costs and fund the development of new, powerful tools for the scientific community. To contribute, please visit our contact page
Meet the Authors
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
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.
Dr. Mosayeb Rostamian
Assistant Professor, Infectious Diseases Research Center
Certified Scientific Reviewer
Google ScholarExpert Review Process
To ensure the highest quality and scientific accuracy, this tool's underlying algorithms, formulas, and edge-case handling have been thoroughly reviewed and validated by Dr. Mosayeb Rostamian.
The "Reviewed By" badge signifies that an independent expert has evaluated the tool's logic to guarantee accuracy and alignment with the current consensus in the scientific community.