Calculate Molecular Weight Of Protein From Amino Acid

Protein Molecular Weight Formula:

\[ MW = \sum (AA\ MW) - (n-1) \times 18.015 \]

Protein Molecular Weight:

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1. What Is Protein Molecular Weight Calculation?

Protein molecular weight calculation determines the mass of a protein molecule based on its amino acid sequence. This is essential for various biochemical applications including protein purification, electrophoresis, and mass spectrometry analysis.

2. How Does The Calculator Work?

The calculator uses the formula:

\[ MW = \sum (AA\ MW) - (n-1) \times 18.015 \]

Where:

\( MW \) — Molecular weight of the protein (g/mol)
\( AA\ MW \) — Molecular weight of individual amino acids (g/mol)
\( n \) — Number of amino acids in the sequence
\( 18.015 \) — Molecular weight of water (g/mol)

Explanation: The formula accounts for the water molecules lost during peptide bond formation between amino acids.

3. Importance Of Protein Molecular Weight

Details: Knowing a protein's molecular weight is crucial for protein characterization, purification techniques like gel filtration chromatography, SDS-PAGE analysis, and mass spectrometry applications.

4. Using The Calculator

Tips: Enter the 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.

5. Frequently Asked Questions (FAQ)

Q1: Why subtract water molecules in the calculation?
A: During protein synthesis, each peptide bond formation results in the loss of one water molecule (condensation reaction).

Q2: Does this calculation account for post-translational modifications?
A: No, this calculator provides the theoretical molecular weight based solely on the amino acid sequence without modifications.

Q3: What about N-terminal and C-terminal modifications?
A: The calculation assumes standard amino and carboxyl termini. Special modifications are not included.

Q4: How accurate is this calculation?
A: This provides a theoretical value. Actual experimental values may differ due to protein folding, hydration, and experimental conditions.

Q5: Can I use three-letter amino acid codes?
A: No, this calculator only accepts single-letter amino acid codes without spaces or separators.