Glutamate is found in each of the following microenvironments. For which microenvironment is the effect on the pKa of the glutamate correctly described (select all that apply)?
a. The Glu is near the C-terminus; pKa increases
b. The side chain is fully exposed to water; no effect
c. A lysine is nearby; pKa decreases
d. The Glu is near several hydrophobic residues; no effect
