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Protein Molar Weight Formula:
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Protein molar weight is the mass of one mole of a protein molecule, calculated by summing the molar weights of all amino acids in the protein sequence plus the molecular weight of water (for the terminal groups).
The calculator uses the formula:
Where:
Explanation: The calculator processes the amino acid sequence, sums the molar weights of each amino acid, and adds the molecular weight of water to account for the terminal amino and carboxyl groups.
Details: Knowing a protein's molar weight is essential for various biochemical applications including protein quantification, electrophoresis, chromatography, and drug development.
Tips: Enter the protein amino acid sequence using single-letter codes. The calculator automatically removes non-amino acid characters and converts to uppercase.
Q1: Why is water molecular weight added?
A: During protein synthesis, a water molecule is lost for each peptide bond formed, but the terminal amino and carboxyl groups remain, adding the equivalent of one water molecule to the total weight.
Q2: Does this account for post-translational modifications?
A: No, this calculator provides the theoretical molecular weight based on the amino acid sequence only and does not account for modifications like phosphorylation or glycosylation.
Q3: What about disulfide bonds?
A: Disulfide bond formation results in the loss of two hydrogen atoms (approximately 2.016 g/mol) per bond, which is not accounted for in this calculation.
Q4: Are non-standard amino acids supported?
A: No, this calculator only supports the 20 standard amino acids represented by single-letter codes (A, R, N, D, C, E, Q, G, H, I, L, K, M, F, P, S, T, W, Y, V).
Q5: How accurate is this calculation?
A: This provides a theoretical molecular weight accurate for most applications, but actual experimental values may vary slightly due to isotopic distributions and other factors.