• Prediction of protein charge and pI
  • Since proteins contain charged amino acids, such as Aspartate and Lysine, they exhibit certain charges in different pH buffers. Isoelectric point (pI) is the pH at which the protein charge becomes to zero. The number of charged residues principally determines the pI and charge of a protein. DNAMAN computes the theoretic pI and charges of the current protein sequence in a user-friendly interface.

    1. Choose the Protein | Charge & pH command to display a dialog box.

    2. Select the number of disulfate bonds of the protein. You should provide this information to increase the accuracy of prediction.

    3. The predicted pI is shown in the dialog box. The pI may vary with disulfate bond number in the protein.

    4. If you enter a pH value, then press Enter from the keyboard or press the Charge ? button, DNAMAN will calculate the charge of the current protein sequence at the given pH.

    5. If you enter a charge value, then press the pH ? button DNAMAN will compute the buffer pH value for the protein to exhibit the charge.