Isoelectric Point of Amino Acids with MCAT shortcut

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Amino Acid Isoelectric Point Calculation by Leah4sciIsoelectric point calculations are critical in your biochemistry course and MCAT prep. The isoelectric point or pI gives you the pH at which the molecule has a net zero charge. This comes from a balance of protonation and deprotonation so that all positive and negative charges cancel out.

This video shows you how to calculate amino acid isoelectric point along with a shortcut to help you figure out WHICH pKa to use when given a side chain pKa value.

(Watch on YouTube: Isoelectric Point of Amino Acids. Click cc on the bottom right for video transcript)

Watch Previous Video: Zwitterion and Amino Acid Charge at Given pH value
Watch Next Video: Peptide Charge and Isoelectric Point Shortcut

This is video 6 in the Amino Acids Series. Click for complete series + Practice Quiz and Cheat Sheet


  1. This is the most amazing video I’ve ever learned from. Some prep companies failed to explain this fully like you did, and I found myself making the mistakes you mentioned! This is great, wish I found it a bit earlier.

    • Rim, I’m glad this has been helpful to you! I was a student once too, so I know exactly what you mean. I try to provide the resources I wish I could have had. How long until you have your MCAT exam?

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