Exam 26: Biomolecules: Amino Acids,peptides,and Proteins

Exhibit 26-1 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 Exhibit 26-1.Draw the structure of the predominant form of leucine at pH = 1.50.

Exhibit 26-2 MATCH a structure from the list below to each of the following terms.Place the letter of the structure in the blank to the left of the term which it describes. -_____ a carboxyl-protected amino acid.

Which of the following is a correct representation of the amino acid below? Atoms other than carbon and hydrogen are labeled.

Exhibit 26-1 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 Exhibit 26-1.Draw the structure of the predominant form of leucine at pH = 10.00.

Which of the following contributes most substantially to rate acceleration produced by an enzyme?

Consider the following data for a hypothetical basic amino acid. pK_a 3)15 8)22 10)93 What is the pI of this substance?

Consider the following image. Which level of protein structure is shown here?

Exhibit 26-4 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 Exhibit 26-4.Leu⁵-enkephalin is a pentapeptide contained as the N-terminal sequence of dynorphin.Write the structure of Leu⁵-enkephalin using both the three letter and one letter abbreviations for the amino acids.

Exhibit 26-2 MATCH a structure from the list below to each of the following terms.Place the letter of the structure in the blank to the left of the term which it describes. -_____ a polypeptide which gives four fragments on treatment with chymotrypsin.

Exhibit 26-2 MATCH a structure from the list below to each of the following terms.Place the letter of the structure in the blank to the left of the term which it describes. -_____ an amino acid in its zwitterionic form.

Show how you could prepare the following amino acid starting with the appropriate carboxylic acid.Atoms other than carbon and hydrogen are labeled.

Exhibit 26-2 MATCH a structure from the list below to each of the following terms.Place the letter of the structure in the blank to the left of the term which it describes. -_____ the product of an Edman degradation.

Exhibit 26-2 MATCH a structure from the list below to each of the following terms.Place the letter of the structure in the blank to the left of the term which it describes. -_____ a peptide coupling reagent.

Exhibit 26-1 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 Exhibit 26-1.Show how leucine might be synthesized using the Knowles enantioselective synthesis.

Exhibit 26-4 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 Exhibit 26-4.What fragments would result if dynorphin were cleaved by trypsin?

Classify the following amino acid.Atoms other than carbon and hydrogen are labeled.

Consider the following image. Which level of protein structure is shown here?

Exhibit 26-5 Refer to the data below to answer the following question(s): 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,Val,Val -Refer to Exhibit 26-5.N-Terminal analysis by the Edman method shows saralasin contains sarcosine at the N-terminus.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?

Show the steps involved in a synthesis of the peptide "F-G-I" using the Merrifield procedure.

Which level of protein structure is disrupted upon mild heating or alteration in pH?