Biochemistry: Concepts and Connections
1st Edition
ISBN: 9780321839923
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 3, Problem 15P
The major difference between a protein molecule in its native state and in its denatured state lies in the number of conformations available. To a first approximation, the native, folded state can be thought to have one conformation. The unfolded state can be estimated to have three possible orientations about each bond between residues.
a. For a protein of 100 residues, estimate the entropy change per mole upon denaturation.
b. What must be the enthalpy change accompanying denaturation to allow the protein to be half-denatured at
50o C?
c. WiII the fraction denatured increase or decrease with increasing temperature?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
The major difference between a protein molecule in its native state and in its
denatured state lies in the number of conformations available. To a first ap-
proximation, the native, folded state can be thought to have one conforma-
tion. The unfolded state can be estimated to have three possible orientations
about cach bond between residues.
(a) For a protein of 100 residues, estimate the entropy change per mole upon
denaturation.
(b) What must be the enthalpy change accompanying denaturation to allow
the protein to be half-denatured at 50 °C?
(c) Will the fraction denatured increase or decrease with increasing
temperature?
The major difference between a protein molecule in its native state and inits denatured state lies in the number of conformations available. To a firstapproximation, the native, folded state can be thought to have one conformation. The unfolded state can be estimated to have three possible orientations about each bond between residues.(a) For a protein of 100 residues, estimate the entropy change per moleupon denaturation.(b) What must be the enthalpy change accompanying denaturation to allow the protein to be half-denatured at 50 °C?(c) Will the fraction denatured increase or decrease with increasingtemperature?
Using the data in Table calculate the average amino acid residue weight in a protein of typical composition. This is a useful number to know for approximate calculations
Chapter 3 Solutions
Biochemistry: Concepts and Connections
Ch. 3 - Prob. 1PCh. 3 - Given the following reactions and their...Ch. 3 - The decomposition of crystalline N2O5...Ch. 3 - The oxidation of glucose to CO2 and water is a...Ch. 3 - Prob. 5PCh. 3 - In another key reaction in glycolysis,...Ch. 3 - Assume that some protein molecule, in its folded...Ch. 3 - When a hydrophobic substance like a hydrocarbon is...Ch. 3 - It is observed that as temperature is increased,...Ch. 3 - Suppose a reaction has Ho and So values...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biochemistry and related others by exploring similar questions and additional content below.Similar questions
- Protein A is made up of a single polypeptide chain; The molecular mass of A is 20,000 Da; the A molecule has 2 tryptophan residues, 5 tyrosine residues, and no disulfide bonds. Calculate what absorbance (at 280 nm) a solution of protein A will have at a concentration of 1.0 mg / mL, in a 1 cm cell. Write the calculations you have done.arrow_forwardThe dissociation constant, Kd for a complex between protein A and protein B is 4.1 μM. If the two proteins are mixed together at initial concentrations of [A]= 0.025 μM and [B] = 4.7 μM, calculate (a) the equilibrium concentrations of A, B, and AB (the dimer formed by A and B) (b) the percentage of A bound to Barrow_forwardPeptides and small proteins fold spontaneously in aqueous solution at room temperature. Thus, for a small protein in water, we can say ΔG FOLD < 0. Denoting the unfolded protein as Unf and the folded protein as Fld, we can write the following equation:Unf(aq)--DELTA G FOLD----> Fld(aq)Considering the transition from the unfolded state (in which there are many possible conformations) to the folded state (only one conformation), there is clearly a decrease in the entropy of the protein. However, protein folding is (correctly) described as an entropically driven process.a) Resolve this apparent paradox by identifying the enthalpy (ΔH) and entropy (−TΔS)components involved in protein…arrow_forward
- A protein has molecular mass of 200 kDa when measured by gel filtration. When subjected to SDS PAGE with and without 2-mercaptoethanol (2-ME) the gel shown below was obtained. What is the likely subunit composition of this protein and why? a. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 25 kDa subunits are linked to each other via noncovalent interactions. b. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit via noncovalent interactions. c. The protein has 3 subunits, with molecular masses 100, 75 and 25 kDa that are linked by noncovalent interactions. d. The protein has 4 subunits, with molecular masses 100, 75, 50 and 25 kDa. The subunits are linked by disulfide bonds. e. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit by disulfide bonds.arrow_forwardSuppose you have a solution of a protein, which contains a specific Tyr residue that has an actual (measured) pKa of 8.8. The protein binds a ligand by several noncovalent interactions, one of which is a hydrogen bond in which the Tyr phenolic hydroxyl group must serve as a hydrogen bond donor. Calculate the percentage of the protein molecules in which that tyrosyl residue's phenolic hydroxyl group could serve as a hydrogen bond donor at pH 8.5arrow_forwardThe temperature of unfolding (denaturation) for a particular protein is 50 oC. A replacement of several amino acids within the protein increased the enthalpy of protein unfolding from 7 kJ mol-1 to 9 kJ mol-1 and did not affect the entropy of unfolding.Calculate the temperature of unfolding after the replacement.arrow_forward
- Discuss and compare the potential contributions for tertiary structure in a protein for the side chain of histidine at each of the following pH values: pH 3, pH 7 and pH 10. (pKa of R group = 6.5). Mathematically describe (show work) and use a full paragraph when discussing each pH (reminder: grammar and spelling will be graded.arrow_forwardIf your initial absorbance from undiluted crude dialysate is 4.50, determine the fold dilution needed to yield an absorbance of approximately 0.700. If you want to prepare 1.0 ml of diluted crude, what volume (mL) of crude dialysate must you add? Your Answer: Answer units It is possible to estimate the molar extinction coefficient of a protein from knowledge of its amino acid composition, as shown from your experiences with EXPASY. From the molar extinction coefficient of tyrosine, tryptophan and cystine (cysteine does not absorb appreciably at wavelengths >260 nm, while cystine does) at a given wavelength, the extinction coefficient of the native protein in water can be computed using the following equation: e(Protein) = #(Tyr)*E(Tyr) + #(Trp)*E(Trp) + #(Cystine)*E(Cystine) Where (if A280 measured in water): E (Tyr) = 1490, ɛ (Trp) = 5500, e (Cystine) = 125 Estimate the molar extinction coefficient of lysozyme using the above equation and the amino acid composition data you found…arrow_forwardYou analyze a protein of 100 kDa using SDS-PAGE in the absence and presence of �-mercaptoethanol (BME) and observe the following band pattern in the gels: Which of the following statements about the protein is correct? (the image is attached) a. The protein consists of three polypeptide chains, two of which are connected via S-S bridges. b. The protein consists of two different polypeptide chains connected via S-S bridges. c. The protein has two different folding conformations. d. The protein consists of two different polypeptide chains linked to each other via non-covalent interactions.arrow_forward
- You are super jazzed because your protein is purified and at a concentration of 600 μg in 1.75 ml of buffer. Convert this concentration to mM. Note that biochemisfunase has a molecular weight of 54,321 Daltons (which is just another unit for g/mol). Show your calculations.arrow_forwardExperimental results describing a protein's amino acid composition are useful for estimating the molecular weight (MW) of the entire protein. A quantitative amino acid analysis reveals that bovine cytochrome c contains 1% tryptophan (M, 204) by weight. Calculate the approximate molecular weight of bovine cytochrome c if there is 1 tryptophan residue. Please enter your answer with three significant figures. approximate bovine cytochrome c MW: number of threonine residues: 19.4 20.4 x10³ Bovine chymotrypsinogen has a molecular weight of 25.6 kDa. Amino acid analysis shows that this enzyme is 9% threonine (M, 119). Calculate how many threonine residues are present in a molecule of bovine chymotrypsinogen. Round your answer to the nearest whole number. Incorrect Incorrect Daarrow_forwardAssume that some protein molecule, in its folded native state, has one favored conformation. But when it is denatured, it becomes a “random coil,” with many possible conformations. (a) If we only consider the change in entropy for the protein, what must be the sign of ∆S for the change: native → denatured? (Note: As suggested in the next problem, this does not include solvent effects, which also make significant contributions to ∆S.) (b) How will the contribution of ∆S for native → denatured affect the favorability of the process? What apparent requirement does this impose on ∆H if proteins are to be stable structures?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
BiochemistryBiochemistryISBN:9781319114671Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.Publisher:W. H. Freeman
Lehninger Principles of BiochemistryBiochemistryISBN:9781464126116Author:David L. Nelson, Michael M. CoxPublisher:W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul...BiochemistryISBN:9781118918401Author:Donald Voet, Judith G. Voet, Charlotte W. PrattPublisher:WILEY
BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage Learning
BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning
Fundamentals of General, Organic, and Biological ...BiochemistryISBN:9780134015187Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. PetersonPublisher:PEARSON
Biochemistry
Biochemistry
ISBN:9781319114671
Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:W. H. Freeman
Lehninger Principles of Biochemistry
Biochemistry
ISBN:9781464126116
Author:David L. Nelson, Michael M. Cox
Publisher:W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul...
Biochemistry
ISBN:9781118918401
Author:Donald Voet, Judith G. Voet, Charlotte W. Pratt
Publisher:WILEY
Biochemistry
Biochemistry
ISBN:9781305961135
Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal
Publisher:Cengage Learning
Biochemistry
Biochemistry
ISBN:9781305577206
Author:Reginald H. Garrett, Charles M. Grisham
Publisher:Cengage Learning
Fundamentals of General, Organic, and Biological ...
Biochemistry
ISBN:9780134015187
Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
Publisher:PEARSON
Macromolecules | Classes and Functions; Author: 2 Minute Classroom;https://www.youtube.com/watch?v=V5hhrDFo8Vk;License: Standard youtube license