Why do not all proteins have the same absorption coefficient (ɛ) at 280 nm? Pick one: a.lt is mainly due to the presence of Asp, Glu, Asn, Gln, Arg and His in the protein b.lt is mainly due to the presence of phenylalanine in the protein c.It is mainly due to the presence of tryptophans and tyrosines in the protein d.The statement is incorrect; all proteins have the same (ɛ) at 280 nm

Why do not all proteins have the same absorption coefficient (ɛ) at 280 nm? Pick one: a.lt is mainly due to the presence of Asp, Glu, Asn, Gln, Arg and His in the protein b.lt is mainly due to the presence of phenylalanine in the protein c.It is mainly due to the presence of tryptophans and tyrosines in the protein d.The statement is incorrect; all proteins have the same (ɛ) at 280 nm

Introduction to General, Organic and Biochemistry

11th Edition

ISBN:9781285869759

Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Publisher:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Chapter22: Proteins

Section: Chapter Questions

Problem 22.52P

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Which is incorrect regarding ligand-protein binding reactions? Select one: O If two ligands can bind to the binding site of the protein, competition for binding will occur. O Phosphorylation of the protein is an example of covalent modulation. O Allosteric modulation of the protein's binding site occurs directly at the binding site itself. O Binding reactions are either electrical or hydrophobic in nature. O Allosteric modulation can alter the affinity of the protein for the ligand.
Which is incorrect regarding ligand-protein binding reactions? Select one: Allosteric modulation can alter the affinity of the protein for the ligand. Phosphorylation of the protein is an example of covalent modulation. Allosteric modulation of the protein’s binding site occurs directly at the binding site itself. If two ligands can bind to the binding site of the protein, competition for binding will occur. Binding reactions are either electrical or hydrophobic in nature.
8. The following proteins represent a wide range of molecular weights and isoelectric points. Mr is the molecular weight of a single protein chain. • Protein 1: Mr 68,544; pl 6.11 (monomer) • Protein 2: Mr 29,041; pl 5.32 (dimer) • Protein 3: Mr 15,805; pl 5.7 (dimer) • Protein 4: Mr 12,165; pl 4.74 a. Which protein is the most acidic? Explain your answer. b. Which protein will migrate the slowest in an SDS-PAGE? Explain your answer. c. In what order will these proteins elute from a cation exchanger at pH 8? Explain your answer. d. In what order will these proteins salt out from a pH 7 solution by the dropwise addition of saturated ammonium sulfate? Explain your answer. 5 83°F Cloudy
Some Protein P binds to 1 molecule of X. The fractional binding curve (θ vs. [Ligand]) shows that θ = ⅓ when [X] = 6 mM. What is the Kd for X binding to P?
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When Coomassie Brilliant Blue G-250 binds to the protein in solution, a shift in wavelength from 465 nm to 565 nm occurs, causing the color of the dye to change from (red-orange, blue) to (green, blue).
5 ased on molecular weights of purified (no beta-Me) and (beta-Me) sample, which are 97.4 kDa and 47.2 kDa, what can be said about the number and size of the protein monomers, as well as the nature of the bonds holding together the complete quaternary structure of the proteins?
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From a study of protein A as a function of temperature, we find that the ratio of unfolded protein (Keq = [U]/[F]) is 3.23 x 108 at 27°C and 8.80 x 10-4 at 57°C. Determine AH, AS and TM for this protein. What is the value of Keq at 70°C?