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Isoelectric Point Plugin

This manual gives you a walk-through on how to use the Isoelectric Point Plugin:

Introduction

The isoelectric point ( pI , or sometimes abbreviated asIEP) is the pH at which a particular molecule or surface carries no net electrical charge .

The Isoelectric Point Plugin calculates the gross charge distribution of a molecule as a function of pH. The result appears in a separate window, containing the molecule with the pI and (if enabled) the pH:charge plot. Hovering the mouse over the points of the curve, the pH:charge value pairs appear.

images/download/attachments/1806643/isoelectricpoint.png

Fig. 1 Isoelectric Point Plugin result window

Options

The Isoelectric Point Options window offers the following options to set:

  • **Decimal places: ** the number of decimal places used to display the results
  • Show charge distribution : enabling this option shows the calculated pH:charge plot on the result chart
  • pH step size : the step size for the prediction and display plot

images/download/attachments/1806643/iep_panel.png

Fig. 2 Isoelectric Point Options window