18. Amino Acids and Proteins

Consider the following tripeptide:

b. Give the one-letter and three-letter abbreviations of this tripeptide.

Draw the structural formula for each of the following peptides:

b. KCG

Draw the structural formula for each of the following peptides:

c. His—Met—Gln

Draw the structural formula for each of the following peptides:

c. Val—Arg

Draw the structural formula for each of the following peptides:

d. IYP

Identify the N-terminus and the C-terminus for each of the peptides in Problem 10.18.

a. Ala—Asn—Thr

b. DS

Aspartame, which is commonly known as NutraSweet™, contains the following dipeptide:

d. Draw the structure of the isomer of this dipeptide where the C-terminal and N-terminal amino acids are switched.

Draw the structure of the possible dipeptides formed from one alanine combining with one cysteine.

Identify the N-terminus and the C-terminus for each of the peptides in Problem 10.18.

c. Val—Arg

Identify the N-terminus and the C-terminus for each of the peptides in Problem 10.18.

d. IYP

Identify the N-terminal and C-terminal amino acids of the peptide.

Identify the amino acids present in the peptide shown and name the peptide using the three-letter abbreviations.

Write structural formulas for the two dipeptides that contain leucine and aspartate.

Use the three-letter abbreviations to name all tripeptides that contain valine, methionine, and leucine.

Identify the amino acids in the following dipeptide and tripeptide, and write the abbreviated forms of the peptide names. Copy the dipeptides, draw a box around the peptide bonds, and use an arrow to identify the α-carbon atoms. Draw a circle around the R groups, and indicate if the R groups are neutral, polar, acidic, or basic.

a.