Calculate the isoelectric point of glutamic acid (E)

Explain the order of elution (with a buffer of pH 4) of the following pairs of amino acids through a column packed with Dowex 50:

b. serine before alanine

Which has a higher percentage of negative charge at physiological pH (7.4), leucine with pI = 5.98 or asparagine with pI = 5.43?

Draw the electrophoretic separation of Trp, Cys, and His at pH 6.0.

Calculate the isoelectric point of tyrosine (Y)

Explain why the pI of lysine is the average of the pKa values of its two protonated amino groups.

a. What percentage of the a-amino group of lysine will be protonated at its pI?

<25%, 50%, >75%

b. Answer the same question for the e-amino group of lysine

a. Which amino acid has the lowest pI value?

b. Which amino acid has the highest pI value?

(a) The isoelectric point (pI) of phenylalanine is pH 5.5. Draw the structure of the major form of phenylalanine at pH values of 1, 5.5, and 11.