What is total charge of a Val-His-Asp tripeptide @ pH 11?
Val NH3 pKa = 9.62
His pKr = 6.00
Asp pKr = 3.65 & pKa = 1.88
If I'm understanding this correctly, at pH 11, given those pKa and pKr values, both amino groups would be deprotonated. Long before that, both carboxyl groups would also be deprotonated, so the answer should be -2. Is this correct?
Also, a question that the book doesn't answer and I don't see my Prof. until Friday so I;m asking here. Being that the N-terminus is now farther away from the C-terminus, does this not affect pKa values for the C-terminus carboxl group?