Exam 24: Amino Acids, Peptides, and Proteins

In an electrophoresis carried out at pH 9.0, does phenylalanine migrate toward the cathode, migrate toward the anode, or not migrate at all? Explain briefly.

An amino acid analyzer can be used to determine:

Draw the dipeptide Val-Tyr.

Give a detailed, stepwise mechanism for the formation of the activated acyl derivative from the reaction of an amino acid with N,N'-dicyclohexylcarbodiimide.

Which of the following amino acids has an isoelectric pH of 3.2?

Proteins which provide all the essential amino acids in about the right proportions are called:

Show where trypsin would cleave the peptide shown below.

Which of the following terms best describes the side chain of valine?

Treatment of a peptide which contains disulfide linkages with peroxyformic acid yields a peptide which contains what new amino acid residue?

What is the net charge of arginine in a solution of pH 10.0?

Provide the structure of Thr-Gln-Met.

Provide a structure of the dipeptide Val-Lys-Glu at biological pH.

Provide the Fischer projection of L-aspartic acid.

Addition of alanine to distilled water will produce:

Draw the form of L-lysine which is present at biological pH.

Which of the following fragments would not result when the decapeptide Asn-Gly-Lys-Phe-Pro-Arg-Gly-Leu-Lys-Ser is treated with trypsin?

What is the major force responsible for the formation of an α-helix in protein secondary structure?

How can an α-ketoacid be converted to an α-aminoacid?

Draw the structure of the tetrapeptide Ser-Leu-Phe-Pro.

Which of the following will result in removal of a benzyl ester protecting group?