Exam 15: Biomolecules: Amino Acids, Peptides, and Proteins

Instructions: Consider the following structure. Based on this structure answer the following question(s). Refer to instructions. How many other peptides could be formed from this same combination of amino acids?

Which of the following amino acids migrates to the negative electrode on paper electrophoresis at a pH of 7.0?

Instructions: Refer to the data below to answer the following question(s). Porcine dynorphin is a neuropeptide having 17 amino acid residues. Its structure is shown below. Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln Refer to instructions. What fragments would result if dynorphin were cleaved by trypsin?

What are the R/S designations of the two stereocenters of L-threonine?

Instructions: Match a term from the list below to each definition.

Instructions: Refer to the data below to answer the following question. $\underline{Amino~ Acid}~~~~~~~\underline{Isoelectic~ point}$ Aregrine $~~~~~~~~~~~~~~~~~~~$ 10.76 Glutamic Acid $~~~~~~~~~~~~$ 3.22 Tryptophan $~~~~~~~~~~~~~~~$ 5.89 Refer to instructions. The most basic amino acid is __________.

Which of the following amino acids migrates to the positive electrode on paper electrophoresis at a pH of 7.0?

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. Draw the condensed structure for leucine, and label all chirality centers with an asterisk and identify the amine as primary, secondary or tertiary.

To what structural feature does the term "tertiary structure" refer?

Which of the following amino acids would contain the highest concentration of zwitterions at pH 5.90?

Instructions: Refer to the data below to answer the following question. $\underline{Amino~ Acid}~~~~~~~\underline{Isoelectic~ point}$ Aregrine $~~~~~~~~~~~~~~~~~~~$ 10.76 Glutamic Acid $~~~~~~~~~~~~$ 3.22 Tryptophan $~~~~~~~~~~~~~~~$ 5.89 Refer to inatructions. The most acidic amino acid is ____.

An enzyme classified as a ligase would be associated with a reaction than involves the:

Refer to the data below to answer the following questions: The octapeptide saralasin is a specific antagonist of angiotensin II. A derivative of saralasin is used therapeutically as an antihypertensive. Amino acid analysis of saralasin show the presence of the following amino acids: Ala, Arg, His, Pro, Sar, Tyr, Val₂ Refer to instructions. Partial hydrolysis of saralasin with dilute hydrochloric acid yields the following fragments: Tyr-Val-His Sar-Arg-Val His-Pro-Ala Val-Tyr-Val Arg-Val-Tyr What is the structure of saralasin? Sar-Arg-Val \nobreakspace\nobreakspace\nobreakspace\nobreakspace Arg-Val-Tyr \nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace Val-Tyr-Val \nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace Tyr-Val-His \nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace\nobreakspace His-Pro-Ala

To what structural feature does the term "secondary structure" refer?

Instructions: Refer to the data below to answer the following question. $\underline{Amino~ Acid}~~~~~~~\underline{Isoelectic~ point}$ Aregrine $~~~~~~~~~~~~~~~~~~~$ 10.76 Glutamic Acid $~~~~~~~~~~~~$ 3.22 Tryptophan $~~~~~~~~~~~~~~~$ 5.89 Refer to instructions. At what pH would you carry out an electrophoresis experiment if you wanted to separate a mixture of lysine, aspartic acid and phenylalanine? Explain.

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. Draw the structure of the predominant form of leucine at pH = 1.50.

Instructions: Consider the following structure. Based on this structure answer the following question(s). Refer to instructions. Identify the C-terminal amino acid and the N-terminal amino acid.

To what structural feature does the term "quaternary structure" refer?

Which of the following amino acids has an aromatic side chain?