Molar Mass Of Protein Calculator

Protein Molar Mass Formula:

\[ MW (g/mol) = \sum (AA \text{ molar mass}) \]

Protein Molar Mass:

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1. What is Protein Molar Mass?

Protein molar mass represents the mass of one mole of a protein molecule, calculated as the sum of the molar masses of its constituent amino acids. It's typically expressed in grams per mole (g/mol) and is essential for various biochemical calculations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ MW (g/mol) = \sum (AA \text{ molar mass}) \]

Where:

\( MW \) — Molar mass in grams per mole
\( AA \) — Individual amino acids in the protein sequence
The calculation includes the mass of water (18.02 g/mol) for the terminal groups

Explanation: The calculator sums the molar masses of all amino acids in the sequence plus the mass of water that is lost during peptide bond formation but must be accounted for in the complete molecular weight.

3. Importance of Protein Molar Mass Calculation

Details: Knowing a protein's molar mass is crucial for laboratory work including protein quantification, concentration calculations, electrophoresis, chromatography, and various biochemical assays.

4. Using the Calculator

Tips: Enter the protein's amino acid sequence using single-letter codes (e.g., "MALWMRLLPLL"). The calculator will automatically remove any non-amino acid characters and calculate the molar mass.

5. Frequently Asked Questions (FAQ)

Q1: Why is water mass added in the calculation?
A: During protein synthesis, water is removed when peptide bonds form. The calculated mass includes this water to represent the complete molecular weight of the protein.

Q2: Does this account for post-translational modifications?
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 disulfide bonds?
A: Disulfide bond formation involves loss of hydrogen atoms, but this calculator uses standard amino acid masses and doesn't account for this specific modification.

Q4: How accurate is this calculation?
A: This provides a theoretical molecular weight based on amino acid composition. Actual measured mass may vary slightly due to isotopic distribution and other factors.

Q5: Can I use three-letter amino acid codes?
A: No, this calculator only accepts single-letter amino acid codes. Convert three-letter codes to single-letter format before calculation.