Concept explainers
(a)
Interpretation: The reagents used in the determination of the amino acid sequence of a small peptide should be determined.
Concept Introduction: A peptide bond is present between the two amino acids in a protein. During the formation of a peptide bond, a molecule of water is released. The amino group of an amino acid gets associated with the carboxyl group of another. Polypeptides and proteins are the chains formed by the amino acids.
(a)
Answer to Problem 1P
The reagent used in the determination of the amino acid sequence of a small peptide is phenyl isothiocyanate.
Explanation of Solution
The reagent used in the determination of the amino acid sequence of a small peptide is phenyl isothiocyanate.
Phenyl isothiocyanate shows a reaction with an uncharged N-terminal amino group. It occurs under the slightly alkaline conditions and forms a cyclical phenyl thiocarbamoyl derivative. It can sequence up to 30 amino acids accurately with modern machines. It is proficient of over 99% proficiency per amino acid.
(b)
Interpretation: The reagent that can undergo reversible denaturation if a protein lacks disulfide bonds should be determined. Also, the reagent needed when the disulfide bonds are present should be determined.
Concept Introduction: A peptide bond is present between the two amino acids in a protein. During the formation of a peptide bond, a molecule of water is released. The amino group of an amino acid gets associated with the carboxyl group of another. Polypeptides and proteins are the chains formed by the amino acids.
(b)
Answer to Problem 1P
The reagent for the reversible denaturation is urea. Beta-mercaptoethanol is used to reduce the disulfide bonds.
Explanation of Solution
The reagent that can undergo reversible denaturation if a protein lacks disulfide bonds is urea.
If the disulfide bonds are present, then the reagent needed is beta-mercaptoethanol. This reagent is used to reduce the disulfide bonds.
(c)
Interpretation: The reagent useful for the peptide bonds hydrolysis present on the carboxyl side of
Concept Introduction: A peptide bond is present between the two amino acids in a protein. During the formation of a peptide bond, a molecule of water is released. The amino group of an amino acid gets associated with the carboxyl group of another. Polypeptides and proteins are the chains formed by the amino acids.
(c)
Answer to Problem 1P
The reagent required is chymotrypsin.
Explanation of Solution
The reagent useful for the peptide bonds hydrolysis present on the carboxyl side of aromatic residues is chymotrypsin which specifically cleaves the C-terminal side of aromatic acid residues.
(d)
Interpretation: The reagent useful for the peptide bonds cleavage on the carboxyl side of methionine should be determined.
Concept Introduction: A peptide bond is present between the two amino acids in a protein. During the formation of a peptide bond, a molecule of water is released. The amino group of an amino acid gets associated with the carboxyl group of another. Polypeptides and proteins are the chains formed by the amino acids.
(d)
Answer to Problem 1P
The reagent useful for thepeptide bonds cleavage on the carboxyl side of methionine is CNBr or cyanogen bromide.
Explanation of Solution
The reagent useful for the peptide bonds cleavage on the carboxyl side of methionine is CNBr. It is also known as cyanogen bromide. It is a solid and colorless inorganic compound. It is extensively used to change the biopolymers, fragment proteins and peptides. It generally cleaves the C-terminus of methionine and produces other compounds.
(e)
Interpretation: The reagent for hydrolysis of peptide bonds on the carboxyl side of lysine and arginine residues should be determined.
Concept Introduction: A peptide bond is present between the two amino acids in a protein. During the formation of a peptide bond, a molecule of water is released. The amino group of an amino acid gets associated with the carboxyl group of another. Polypeptides and proteins are the chains formed by the amino acids.
(e)
Answer to Problem 1P
The reagent for hydrolysis of peptide bonds on the carboxyl side of lysine and arginine residues is trypsin.
Explanation of Solution
The reagent for hydrolysis of peptide bonds on the carboxyl side of lysine and arginine residues is trypsin.
Trypsin is generally formed in the small intestine. It is formed by the activation of trypsinogen. Trypsin usually cuts the peptide chains primarily at the carboxyl side of the lysine or arginineamino acids. It is used for many
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Chapter 3 Solutions
SAPLINGPLUS F/BIOCHEM+ICLICKER REEF-CODE
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- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning