1. What is Peptide Molecular Formula?

The molecular formula of a peptide represents the exact number of atoms of each element in the molecule. For peptides, this typically includes carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sometimes sulfur (S).

2. How Does the Calculator Work?

The calculator sums the elemental composition of each amino acid in the sequence and accounts for peptide bond formation (loss of water) and any modifications:

Where:

• Each amino acid contributes its specific elemental composition
• Each peptide bond results in the loss of one water molecule (H₂O)
• Modifications like acetylation or amidation add specific elements

3. Importance of Molecular Formula

Details: The molecular formula is essential for calculating molecular weight, elemental analysis, and understanding the chemical properties of the peptide.

4. Using the Calculator

Tips: Enter the amino acid sequence in single-letter code (e.g., "ACDEFGHIKLMNPQRSTVWY"). Select any modifications like N-terminal acetylation or C-terminal amidation if applicable.

5. Frequently Asked Questions (FAQ)

Q1: What amino acids are supported?
A: All standard 20 amino acids (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y).

Q2: How are modifications handled?
A: N-terminal acetylation adds C₂H₂O. C-terminal amidation replaces OH with NH₂ (adds NH, removes O).

Q3: Does this include disulfide bonds?
A: No, this calculator doesn't account for disulfide bond formation between cysteines.

Q4: Can I use lowercase letters?
A: Yes, the calculator will convert to uppercase automatically.

Q5: How accurate is this calculation?
A: It's accurate for standard amino acids and the specified modifications. For non-standard amino acids or complex modifications, manual adjustment may be needed.