Protein Charge Calculator

Formula

To calculate the Net Charge (Q) of a protein:

\[ Q = (n_R - n_D + n_K + n_H) \times 1.602 \times 10^{-19} \]

Where:

\(Q\) is the Net Charge of the protein (C)
\(n_R\) is the number of Arginine residues
\(n_D\) is the number of Aspartic acid residues
\(n_K\) is the number of Lysine residues
\(n_H\) is the number of Histidine residues
\(1.602 \times 10^{-19}\) C is the elementary charge

What is Protein Charge?

A protein charge, also known as a net charge, refers to the overall electrical charge of a protein molecule. This charge is determined by the sum of the charges of the amino acids that make up the protein. Each amino acid has a specific charge, either positive, negative, or neutral, depending on its pH level. The protein's charge can influence its structure, function, and interactions with other molecules. It is also crucial in processes such as protein separation and purification.

Example Calculation 1

Let's assume the following values:

Number of Arginine residues (\(n_R\)) = 20
Number of Aspartic acid residues (\(n_D\)) = 10
Number of Lysine residues (\(n_K\)) = 15
Number of Histidine residues (\(n_H\)) = 5

Using the formula:

\[ Q = (20 - 10 + 15 + 5) \times 1.602 \times 10^{-19} = 4.008 \times 10^{-18} \, \text{C} \]

The Net Charge is \(4.008 \times 10^{-18}\) C.

Example Calculation 2

Let's assume the following values:

Number of Arginine residues (\(n_R\)) = 10
Number of Aspartic acid residues (\(n_D\)) = 5
Number of Lysine residues (\(n_K\)) = 10
Number of Histidine residues (\(n_H\)) = 5

Using the formula:

\[ Q = (10 - 5 + 10 + 5) \times 1.602 \times 10^{-19} = 3.204 \times 10^{-18} \, \text{C} \]

The Net Charge is \(3.204 \times 10^{-18}\) C.