Answer the following eight questions a through h based upon

Answer the following eight questions (a through h) based upon a tripeptide sequence of the following amino acids (one-letter codes are given): S L E

c) What is the overall charge on the tripeptide at physiological pH (pH 7.4)?

e) What is the overall charge of the tripeptide below pH 1.0?

f) What is the overall charge of the tripeptide at pH 11.5 If someone could explain this to me it would be greatly appreciated!

Answer:

SLE = Serine-Leucine-Glutamate

c) What is the overall charge on the tripeptide at physiological pH (pH 7.4)?

At physiological pH this peptide is -1

Glutamate side chain has -1 charge and the amino (+1) and Carboxy (-1) = -1 net charge at pH 7.4

e) What is the overall charge of the tripeptide below pH 1.0?

At pH 1, this peptide is +1

Only the amino terminal is charged due to protonation.

f) What is the overall charge of the tripeptide at pH 11.5

At pH 1, this peptide is -2

Only the carboxy terminal and the glutamate side chain are charged due to deprotonation.