Exam 29: Amino Acids and Proteins

Why does the formation of salts of a racemic mixture of N-acetyl valine with a single enantiomer of -methylbenzylamine enable the separation of the two enantiomers of N-acetyl valine?

Below is a proposed method for resolving a racemic mixture of (R)- and (S)-phenylalanine. Upon separation of the products, will this method produce (R)- or (S)-phenylalanine?

Which of the following amino acids is achiral?

Which of the following is the correct structure for aspartic acid at pH = 1?

Which of the following is (are) globular protein(s)?

Why can glycine not be resolved into two enantiomers?

What is the configuration of naturally occurring amino acids?

What is (are) the missing reagent(s) in the reaction below?

What is the appropriate sequence of reaction conditions used to synthesize valine from acetamidomalonic ester?

Which of the following is the major advantage of the Merrifield synthesis of peptides?

What is the IUPAC or common name for the following compound?

What are the basic steps in the Merrifield peptide synthesis?

Which of the following correctly describes a peptide bond?

Below is a 2D chromatogram that shows the separation of five amino acids. In this technique, the amino acid mixture is first separated by chromatography using a polar solvent system. Then the plate is rotated 90°, and the amino acids are further separated by electrophoresis. Identify the spots obtained from a mixture of Trp, Glu, Lys, Ile and Thr. A table with isoelectric points is included to aid in solving this problem. amino acid pI value Trp 5)9 Glu 3)2 Lys 9)7 Ile 6)0 Thr 5)6

What amino acid is at the N-terminus of the following peptide?

Which of the following correctly describes the tertiary structure of a peptide?

Why is the s-trans form of an amide bond more stable?

Reaction of a polypeptide, composed of 12 amino acids, with carboxypeptidase A releases Met (C-terminal amino acid). The polypeptide undergoes partial hydrolysis to give 12 groups of peptides. Use the groups of overlapping amino acids to determine the proper sequence of this polypeptide. Note: Since these lists of peptides are separated by commas, they are not necessarily in the proper sequence. 1. Ser, Lys, Trp 2. Gly, His, Ala 3. Glu, Val, Ser 4. Leu, Glu, Ser 5. Met, Ala, Gly 6. Ser, Lys, Val 7. Glu, His 8. Leu, Lys, Trp 9. Lys, Ser 10. Glu, His, Val 11. Trp, Leu, Glu 12. Ala, Met

Which is the correct structure for the amino acid valine?

Which of the following correctly describes a protein?