Concept explainers
Videos
(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
Want to see more full solutions like this?
Chapter 3 Solutions
BIOCHEMISTRY
- Please draw out the mechanism with curved arrows showing electron flow. Pyruvate is accepted into the TCA cycle by a “feeder” reaction using the pyruvate dehydrogenase complex, resulting in acetyl-CoA and CO2. Provide the mechanism for this reaction utilizing the TPP cofactor. Include the roles of all cofactors.arrow_forwardPyruvate is accepted into the TCA cycle by a “feeder” reaction using the pyruvate dehydrogenase complex, resulting in acetyl-CoA and CO2. Provide the mechanism for this reaction utilizing the TPP cofactor. Include the roles of all cofactors.arrow_forwardThe mitochondrial ATP synthase has 10 copies of the F0 subunit “c”, and the [H ] in the mitochondrial inner membrane space (IMS) is 6.31 x 10-8 M and the [H + ] in the matrix is 3.16 x 10-9 M. Calculate the minimum membrane potential (∆Ψ) necessary to make ATP synthesis thermodynamically favorable. [Assume ∆G' ofphosphate hydrolysis of ATP is - 45 kJ/mol.]arrow_forward
- B- Vitamins are converted readily into important metabolic cofactors. Deficiency in any one of them has serious side effects. a. The disease beriberi results from a vitamin B 1 (Thiamine) deficiency and is characterized by cardiac and neurological symptoms. One key diagnostic for this disease is an increased level of pyruvate and α-ketoglutarate in the bloodstream. How does this vitamin deficiency lead to increased serumlevels of these factors? b. What would you expect the effect on the TCA intermediates for a patient suffering from vitamin B 5 deficiency? c. What would you expect the effect on the TCA intermediates for a patientsuffering from vitamin B 2 /B 3 deficiency?arrow_forwardPyruvate is accepted into the TCA cycle by a “feeder” reaction using the pyruvate dehydrogenase complex, resulting in acetyl-CoA and CO2. Provide a full mechanism for this reaction utilizing the TPP cofactor. Include the roles of all cofactors.arrow_forwardMap out all of the metabolic pathways in the liver cell. Draw out the structures and names of all compounds neatly by hand and the pathways responsible for metabolizing them. Some examples are: Glycolysis/gluconeogenesis, PPP, Glycogenesis/glycogenolysis, Krebs, ETC, selectamino acid pathways (Ala, Glu, Asp) Lipogenesis/lipolysis. Citrate/MAS/glycerol phosphate shuttlesystems, and the Cori/Glc-Ala cycles. Rules:-Draw both a mitochondrial area of metabolism and a cytoplasmic area of metabolism.-Draw the liver and its roles in glucose recycling (Cori cycle/Glc-Alanine recycling)-Avoid drawing the same molecule twice (except for separate mitochondrial/cytoplasmic populations. i.e. Design the PPP/Glycolysis so that GAP is only drawn once)-Label Carbon 4 of glucose and highlight where you would expect to find it in EVERY compound in whichit is present.-Have one or two locations for NADH/NADPH/ATP/GTP/CoQH2 – many arrows will come to/from thesespots.arrow_forward
- a. Draw the Krebs Cycle and show the entry points for the amino acids Alanine,Glutamic Acid, Asparagine, and Valine into the Krebs Cycle. (Include name of Enzymes involved) b. How many rounds of Krebs will be required to waste all Carbons of Glutamic Acid as CO2? (Show by drawing out the mechanism that occurs)arrow_forwardThe malate-aspartate shuttle allows malate to be exchanged for aspartate acrossthe inner mitochondrial membrane. (a) Describe the role of the malate-aspartate shuttle in liver cells under HIGHblood glucose conditions. Be sure to explain your answer. (b) Describe the role of the malate-aspartate shuttle in liver cells under LOW blood + glucose conditions.arrow_forward(a) Write out the net reaction, calculate ∆E ̊' for the reaction, and calculate the standard free-energy change (∆G°') for the overall oxidation/reduction reaction. (h) How many moles of ATP could theoretically be generated per mole of FADH2 oxidized by this reaction, given a ∆G ̊' of ATP synthesis of + 31 kJ/mol? How many moles of ATP could be generated per mole of FADH2 oxidized by this reaction under more typical cellular conditions (where ∆G' of ATP hydrolysis is ~ -50 kJ/mol)? Be sure to show your work and explain your answer.arrow_forward
- Indicate for the reactions below which type of enzyme and cofactor(s) (if any) would be required to catalyze each reaction shown. 1) Fru-6-P + Ery-4-P <--> GAP + Sed-7-P2) Fru-6-P + Pi <--> Fru-1,6-BP + H2O3) GTP + ADP <--> GDP + ATP4) Sed-7-P + GAP <--> Rib-5-P + Xyl-5-P5) Oxaloacetate + GTP ---> PEP + GDP + CO26) DHAP + Ery-4-P <--> Sed-1,7-BP + H2O7) Pyruvate + ATP + HCO3- ---> Oxaloacetate + ADP + Piarrow_forwardThe phosphate translocase is an inner mitochondrial membrane symporter that transports H2PO4- and H+ into the mitochondrial matrix. Phosphate is a substrate for Complex V (the ATP Synthase), the enzyme that couples the synthesis of ATP to the H+ gradient formed by the electron transport chain. (a) Bongotoxin is a hypothetical compound that inhibits the phosphate translocase of the inner mitochondrial membrane. Explain why electron transport from NADH to O2 stops when bongotoxin is added to mitochondria (i.e., why do electrons stop flowing through the electron transport chain even with an abundance of NADH and O 2 present). What effect will the addition of the weak acid dinitrophenol (DNP) to the cytosol have on electron transport in bongotoxin-inhibited mitochondria? Be sure to explain your answers. (b) How much free energy is released (in kJ) when one mole of protons flows from the mitochondrial inner membrane space (IMS) to the mitochondrial matrix when the [H+ ] in the IMS is 7.9 x…arrow_forwardWhen TMPD/ascorbate is added to mitochondria as a source of electrons (TMPD/ascorbate reduce cytochrome c directly) oxygen is reduced to H2O by the electron transport chain (ETC).(a) Approximately how many ATPs would result per O2 consumed when electrons come from TMPD/ascorbate? (b) If dinitrophenol (DNP) is added to the mitochondria in (a) above, what effect would DNP have on the yield of ATPs per O2 reduced from TMPD/ascorbate electrons?arrow_forward
BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning
Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage Learning
Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
Biology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781337408332Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning