What is Protein Molecular Weight Calculator?
A protein molecular weight calculator is an essential tool for biochemists and molecular biologists to determine the mass of a protein based on its amino acid sequence. This calculation is crucial for various applications including SDS-PAGE analysis, protein purification, mass spectrometry, and biochemical research. By inputting the protein sequence, researchers can instantly obtain accurate molecular weight values needed for experiment planning and data analysis.
Protein MW Calculator
Calculation Formula
The molecular weight is calculated using the formula:
MW = Σ(amino acid molecular weights) - (n-1)*18.0153
Where n = number of amino acids and 18.0153 = molecular weight of water removed during peptide bond formation.
How to Use
1. Enter your protein sequence using single-letter amino acid codes
2. Click "Calculate Molecular Weight"
3. View results instantly
4. Use clear button to reset
5. Refer to amino acid table below for reference
Amino Acid Molecular Weight Table
| Amino Acid | 1-letter Code | Molecular Weight (Da) |
|---|---|---|
| Alanine | A | 89.09 |
| Arginine | R | 174.20 |
| Asparagine | N | 132.12 |
Advantages & Disadvantages
Advantages:
- Instant calculation saves laboratory time
- Eliminates manual calculation errors
- Essential for experiment planning
- Supports various research applications
- User-friendly interface
Disadvantages:
- Doesn't account for post-translational modifications
- Assumes average isotopic composition
- Requires pure protein sequence input
- Doesn't consider protein folding
- Limited to natural amino acids
FAQs
1. How accurate is the protein molecular weight calculator?
The calculator provides theoretical molecular weight based on average isotopic masses. While highly accurate for most applications (±1 Da), actual experimental values may vary slightly due to natural isotopic distributions and post-translational modifications.
2. Can I use lowercase letters for amino acids?
Yes, the calculator automatically converts all input to uppercase letters. Both "a" and "A" will be recognized as Alanine.