1. What is the Jay Campbell Peptide MW Equation?

The Jay Campbell peptide molecular weight equation calculates the molecular weight of a peptide chain by summing the molecular weights of its constituent amino acids and subtracting the weight of water molecules lost during peptide bond formation.

2. How Does the Calculator Work?

The calculator uses the peptide molecular weight equation:

Where:

• \( MW \) — Molecular weight of the peptide (g/mol)
• \( MW_{aa} \) — Molecular weight of individual amino acids (g/mol)
• \( length \) — Number of amino acids in the sequence
• 18 — Molecular weight of water (g/mol)

Explanation: For each peptide bond formed, one water molecule is lost (condensation reaction). An n-length peptide has (n-1) peptide bonds.

3. Importance of Peptide MW Calculation

Details: Knowing peptide molecular weight is essential for mass spectrometry analysis, peptide synthesis, molarity calculations, and biochemical experiments.

4. Using the Calculator

Tips: Enter the peptide sequence using single-letter amino acid codes (e.g., "GADV" for Gly-Ala-Asp-Val). The sequence is case-insensitive.

5. Frequently Asked Questions (FAQ)

Q1: Does this include post-translational modifications?
A: No, this calculates the theoretical molecular weight of the unmodified peptide chain.

Q2: What about N-terminal or C-terminal modifications?
A: This calculator assumes free amino and carboxyl termini. For modified termini, you would need to manually adjust the result.

Q3: How accurate is this calculation?
A: This provides the theoretical average molecular weight. For exact mass (including isotopic distribution), more specialized tools are needed.

Q4: What if my peptide contains non-standard amino acids?
A: This calculator only handles the 20 standard amino acids. For non-standard residues, you would need to calculate manually.

Q5: Why subtract water for each peptide bond?
A: Peptide bond formation is a condensation reaction that releases one water molecule per bond formed.