7. Chalcone isomerase catalyzes the reaction illustrated below. A series of modification experimentswere performed on this enzyme to identify which amino acid residues might be in the active site andwhich might promote the cyclization reaction.OHHo.НоExplain the following results:A) Acetic anhydride treatment inhibited enzyme activity.B) Pyrocarbonate inhibited activity and was found to modify 7 residues. However, this enzymeonly contains 6 His and modification of these did not affect activity.C) lodoacetate inhibited activity but this effect coult be decreased in the presence of substrate orproduct.D) Methane methanethiol sulfonate modified the enzyme but did not inhibit catalytic turnover. Inaddition, this modification was reversed in the presence of B-mercaptoethanol.keNyons Rengent

Chalcone isomerase is an enzyme in Flavonoid pathway of Anthocyanine biosynthesis and catalyze the…

Answered: 7. Chalcone isomerase catalyzes the…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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1 ).Which of the following accurately describes substrate specificity for serine proteases? A.The binding cleft B.Mg2+ metal activated enzyme C.The catalytic triad D.Facilitates redox chemistry E.Stabilizes the transition state 2). Which of the following amino acid residues would not provide a side chain for acid-base catalysis at physiological pH? select all that apply leucine aspartic acid histidine lysine Please answer both correct i will give u upvote.
4. a) Structures A, B and C are derivatives of penicillin Н NHH +x A i) ii) iii) CO₂H HH Ex B CO₂H R Describe briefly how the activity of B and C compares with A. b) The biosynthesis of penicillin involves two amino acids с Name the two amino acids. What is the name of the enzyme inhibited by the penicillin? What does penicillin mimic in bacteria cell wall synthesis?
(i) Describe the mechanism of chymotrypsin in cleaving a peptide bond, highlighting the roles of the catalytice triad for the two phases of the catalytic reactions. Explain the significance of the oxyanion hole for the catalysis. (ii) All serine proteases contain the catalytic triad and these amino acids are positioned in the exact same conformation. Since this is true, why do trypsin and chymotrypsin have such different substrate specificity? What features of the enzyme allow for this situation?
5. For a Michaelis-Menten enzyme, k1 = 5.2 ⅹ 108 M-1 s-1, k-1 = 3.1 ⅹ 104 s-1, and k2 = 3.4 ⅹ 105 s-1. a) Write out the reaction, showing k1, k-1, and k2. Calculate Ks and Km. Does substrate binding approach equilibrium or the steady state? Justify your answer. b) What is kcat for this reaction? Justify your answer. c) Calculate Vmax for the enzyme. The total enzyme concentration is 25 pmol L-1, and each enzyme has two active sites. d) What substrate concentration would be required for the reaction in (c) to reach half of Vmax. Justify your answer mathematically. e) A second Michaelis-Menten enzyme has k1 = 4.2 ⅹ 107 M-1 s-1, k-1 = 6.1 ⅹ 104 s-1, and k2 = 5.3 ⅹ 102 s-1. Which enzyme is most efficient? 6. A pharmaceutical company is trying to develop a
An enzyme catalyzes the reaction M ßàN. The enzyme is present at a concentration of 1 nM, and the Vmax is 2 M s-1. The Km for substrate M is 4 μM. a)Calculate kcat. b)What values of Vmax and Km would be observed in the presence of sufficient amounts of an uncompetitive inhibitor to generate an α’ of 2.0?
Two therapeutics, methotrexate and fluorouracil, inhibit the formation of dTMP, at different points in the synthesis. One is a suicide inhibitor and one is a competitive inhibitor. a. What therapeutic applications are there for inhibiting the synthesis of dTTP? (ie. What are they treating?) b. Identify the which molecule is the competitive inhibitor and which one is the suicide inhibitor and explain how you know.
If the substrate for an enzyme catalyzed reaction contained a negative charge, which of the following amino acids would most likely be present in the active site to provide electrostatic destabilization of the ES complex? Leu Val O Asp O LYS QUESTION 15 What is the function of the histidine in the diagram of the mechanism at right with the substrate, a phenylalanine residue? (n) His Asp Nucleophilic affack by water stabilization of a metal ion covalent catalysis electrostatic attraction of the substrate O acid base catalysis 789 Mustly cloudy Click Save and Submit to save and submit. Click Save All Ansuwers to save all answers. here to search
You have discovered a new enzyme that has a nearly identical active site to chymotrypsin. This new enzyme uses the same catalytic triad and the same reaction mechanism as chymotrypsin. Your new enzyme differs from chymotrypsin because it cuts peptides at the C terminus of polar, non-ionizable R groups. a) Beginning with the first tetrahedral intermediate, draw the mechanism of catalysis that occurs to cleave the tripeptide Asn-Phe-Lys substrate ending your answer with product and free enzyme. b) From the list below, which of the components would most likely be found in the area of the enzyme that substitutes the hydrophobic pocket of chymotrypsin? Very briefly explain your choice(s)., Ser lle Zn Val c) You've constructed a molecule that is able to bind to the 1 tetrahedral intermediate of your new.enzyme, preventing catalysis. From experimental results, you can see that this molecule is only able to bind to the tetrahedral intermediate. Assuming that this enzyme follows…
Lysosyme catalyzes the hydrolysis of the carbohydrate linkage in part of the bacterial cell wall (peptidoglycan layer). 1. Propose a mechanism using general acid/base catalysis 2. Propose a mechanism using covalent catalysis. (An intermediate has been observed that indicates a glycosidic bond to the aspartate).
You have discovered a new enzyme that has a nearly identical active site to chymotrypsin. This new enzyme uses the same catalytic triad and the same reaction mechanism as chymotrypsin. Your new enzyme differs from chymotrypsin because it cuts peptides at the C terminus of polar, non- ionizable R groups. A) Beginning with the first tetrahedral intermediate, draw the mechanism of catalysis that occurs to cleave the tripeptide Asn- Phe- Lys substrate ending your answer with the product and free enzyme. B) From the list below, which of the components would most likely be found in the area of the enzyme that substitutes the hydrophobic pocket of chymotrypsin? Very briefly explain your choice(s): Ser ile Zn+ Val C) You've constructed a molecule that is able to bind to the 1st tetrahedral intermediate of your new enzyme, preventing catalysis. From experimental results, you can see that this molecule is only able to bind to the tetrahedral intermediate. Assuming that this enzyme follows…
Most bacterial mutants that require isoleucine for growth also require valine.Why? Which enzyme or reaction would be defective in a mutant requiringonly isoleucine (not valine) for growth?
Given the following reaction, identify the class and subclass of the enzyme involved. H. CH2OH H-C-OH C=0 но-с-н но-с-н H-C-OH H-C-OH H-C-OH H-C-OH CH2OPO,2 CH2OPO,2- Class: [ Select] [ Select ] Ligase Hydrolase Lyase Subcla Transferase Isomerase Oxidoreductase

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