Charge and isoelectric point of peptides are determined by the individual amino acids. Both the backbone groups (N and C terminus) and the individual side chains.
The previous video showed you how to find the charge and pI of individual amino acids. This tutorial shows you how to find them for a group of amino acids bound together. This includes a time-saving shortcut from longer peptide chains.
(Watch on YouTube: Peptide Charge and pI. Click cc on the bottom right for video transcript)