Question

If you sketch the titration curve for the following protein (Ser−Tyr−Ser−Met−Glu−His−Phe−Arg−Trp−Gly−Lys−Pro−Val), near what pH values would you expect the curve to exhibit inflections? Assume the pKas of the N- and C-termini are 7.9 and 3.8, respectively.

For side chains, assume the pKa values given. The curve will exhibit infections corresponding to ___ group(s) titrating near 4 (____), ___ group(s) near 6.5 (____), ____ group(s) near 8 (____), ___ group(s) near 10 (____) and ___ group(s) near 12 (___).

Match the items in the left column to the appropriate blanks in the sentence on the right.

one

two

carboxyl terminus and glutamic side chain

histidine

N-terminus and lysine

tyrosine

arginine

glutamic side chain

lysine

carboxyl terminus

N-terminus

cystein

aspartic side chain

lysine and tyrosine

Answer 1

For side chains, assume the pKa values given. The curve will exhibit infections corresponding to carboxyl terminus and glutamic side chain group(s) titrating near 4 (_Two___), histidine ___ group(s) near 6.5 (_one___), N-terminus ____ group(s) near 8 (One____), _lysine and tyrosine __ group(s) near 10 (_ Two___) and arginine ___ group(s) near 12 (_One__).