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Protein Molar Mass Formula:
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Protein molar mass represents the mass of one mole of a protein molecule, typically measured in grams per mole (g/mol). It's calculated by summing the masses of all amino acids in the protein sequence and subtracting the mass of water molecules lost during peptide bond formation.
The calculator uses the formula:
Where:
Explanation: For a protein with n amino acids, there are (n-1) peptide bonds, each formed with the loss of one water molecule.
Details: Knowing a protein's molar mass is essential for various biochemical applications including protein quantification, concentration calculations, electrophoresis, chromatography, and structural studies.
Tips: Enter the protein amino acid sequence using single-letter codes (A, R, N, D, C, E, Q, G, H, I, L, K, M, F, P, S, T, W, Y, V). The calculator will automatically remove any non-amino acid characters.
Q1: Why subtract water molecules?
A: During protein synthesis, each peptide bond formation results in the loss of one water molecule, which must be accounted for in the total mass calculation.
Q2: Are post-translational modifications considered?
A: No, this calculator provides the theoretical mass of the unmodified polypeptide chain. Modifications like phosphorylation or glycosylation would add additional mass.
Q3: What about N-terminal and C-terminal groups?
A: The calculation assumes standard protonation states at physiological pH (NH₃⁺ at N-terminus, COO⁻ at C-terminus), which are included in the amino acid masses.
Q4: How accurate is this calculation?
A: This provides a theoretical average mass. For exact mass calculations, isotopic distributions would need to be considered.
Q5: Can I use three-letter codes?
A: No, this calculator only accepts single-letter amino acid codes. Convert three-letter codes to single-letter format before calculation.