pKa

Biological Macromolecules

proteins, amino acids, and the pKa of amino acids

3.5 Sequencing

with strong acids (i.e. 6N HCl) or strong bases or by exhaustive enzymatic

Large Molecules

3.3 pKa's

Chart The pKa's of amino acids

3.3 Acid-Base Equilibria

pKa and the Henderson-Hasselbalch Equation

Henderson-Hasselbalch Equation. Find the pKa of the a-NH3 of valine

on the pKa chart. Then calculate the fraction of valine a-NH3

At any pH above the pKa, the molecule will be more negatively charged.

At any pH below the pKa, the molecule will be more positively charged.

At any pH more than 1.0 unit different than the pKa, you can consider

above the pH was exactly 1.0 different from the pKa, giving an ionization of

This is a very useful chart of the pKa's of the amino acids: