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Molecular Weight Formula:
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Protein molecular weight calculation determines the mass of a protein molecule by summing the atomic masses of all atoms in the molecule, including the terminal water molecule that completes the protein structure during synthesis.
The calculator uses the formula:
Where:
Explanation: The calculation sums the molecular weights of all amino acids in the sequence and adds the weight of one water molecule, which accounts for the hydrolysis that occurs during protein synthesis.
Details: Accurate molecular weight calculation is essential for protein characterization, gel electrophoresis, mass spectrometry analysis, protein purification, and biochemical research applications.
Tips: Enter the protein sequence using single-letter amino acid codes (A, R, N, D, C, E, Q, G, H, I, L, K, M, F, P, S, T, W, Y, V). The sequence can be entered in any case and will be converted to uppercase automatically.
Q1: Why is water added to the molecular weight calculation?
A: Water is added because during protein synthesis, a water molecule is released when amino acids form peptide bonds, but this water must be accounted for in the total molecular weight.
Q2: What are the units of measurement?
A: Molecular weight is calculated in Daltons (Da), where 1 Dalton is defined as one-twelfth the mass of a carbon-12 atom.
Q3: Does this calculator consider modified amino acids?
A: No, this calculator uses standard amino acid molecular weights. Post-translational modifications require specialized calculators.
Q4: How accurate is this calculation?
A: This provides a theoretical molecular weight based on monoisotopic masses. Actual experimental values may vary slightly due to isotopic distribution.
Q5: Can I calculate molecular weight for nucleic acids with this tool?
A: No, this calculator is specifically designed for protein sequences. Different calculations are needed for DNA/RNA sequences.