1. What Is Molecular Weight Calculation?

Molecular weight calculation determines the mass of a protein or peptide based on its amino acid sequence. This is essential for various biochemical applications including protein characterization, electrophoresis, and mass spectrometry.

2. How Does The Calculator Work?

The calculator uses the molecular weight formula:

Where:

• \( AA_{masses} \) — Sum of individual amino acid masses
• \( n \) — Number of amino acids in the sequence
• 18.015 — Molecular weight of water (lost during peptide bond formation)

Explanation: The formula accounts for the mass of individual amino acids and subtracts the mass of water molecules lost during peptide bond formation.

3. Importance Of Molecular Weight Calculation

Details: Accurate molecular weight calculation is crucial for protein research, drug development, biochemical analysis, and understanding protein structure-function relationships.

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 automatically removes non-amino acid characters.

5. Frequently Asked Questions (FAQ)

Q1: What type of molecular weight is calculated?
A: This calculator provides the monoisotopic molecular weight, which is the exact mass based on the most abundant isotopes.

Q2: Does this include post-translational modifications?
A: No, this calculator provides the theoretical molecular weight of the unmodified polypeptide chain.

Q3: How accurate is this calculation?
A: The calculation is based on established monoisotopic masses and provides theoretical values accurate for most research applications.

Q4: Can I calculate molecular weight for non-standard amino acids?
A: This calculator only supports the 20 standard amino acids. Modified amino acids require specialized tools.

Q5: How does this relate to kDa?
A: 1 kDa = 1000 Da. To convert the result to kDa, divide the molecular weight by 1000.