Draw the major product of this aminolysis reaction. Ignore inorganic byproducts. NO 1. excess NH2CH3 2. neutralizing work-up Drawing

Draw a segment of the backbone of a protein that is long enough for three peptide linkages to be present.

For the tripeptide SerArgIle which amino acid residues a. are hydrophilic b. are hydrophobic c. possess polar neutral R groups d. participate in two amide linkages

Consider the tripeptide tyrosylleucylisoleucine. a. Specify its structure using three-letter symbols for the amino acids. b. How many peptide bonds are present within the peptide? c. Which of the amino acid residues has the largest R group? d. Which of the amino acid residues, if any, has an acidic side chain?

22-42 (a) How many atoms of the peptide bond lie in the same plane? (b) Which atoms are they?

Which of the following are true concerning the chemical bond that forms between the carboxyl (RCOOH) group of one amino acid and the amino (RCNH2) group of another? a.The bond is called a peptide bond. b.It is formed by inserting a water molecule between them. c.It is formed by a dehydration reaction. d.A polypeptide has more of these bonds than a protein.

22-49 Based on your knowledge of the chemical properties of amino acid side chains, suggest a substitution for leucine in the primary structure of a protein that would probably not change the character of the protein very much.

Using both three- and one-letter codes for amino acids, write the structures of all possible peptides containing the following amino acids: (a) Val, Ser, Leu (b) Ser, Leu2, Pro

22-44 How can a protein act as a buffer?

For the tripeptide AlaValGly which amino acid residues, if any, a. are hydrophilic b. are hydrophobic c. possess nonpolar R groups d. participate in two amide linkages