Are the given reactions examples of general acid/base catalysis, covalent catalysis, catalysis by approximation (proximity effect), or metal-ion catalysis? Glu HN R' Enzyme substrate complex Glu H HN R' oe ***** Zn2+ Tetrahedral intermediate NMP kinases bring two nucleotides, such as AMP and ATP, together to facilitate the transfer of a phosphoryl group from one nucleotide to the other (creating two ADP). The enzyme positions the adenosine triphosphate (ATP) such that the gamma phosphate group is placed adjacently to the phosphate group of the NMP kinase. This facilitates the transfer of the phosphate between the two molecule. In aspartate ammonia lyase, a deprotonated serine sidechain performs a nucleophilic attack on a carbonyl carbon of the substrate. An active site histidine abstracts a proton from a substrate, making it more reactive, and then donates the proton back to the product. general acid/base catalysis catalysis by approximation metal-ion catalysis covalent catalysis

Are the given reactions examples of general acid/base catalysis, covalent catalysis, catalysis by approximation (proximity effect), or metal-ion catalysis? Glu HN R' Enzyme substrate complex Glu H HN R' oe ***** Zn2+ Tetrahedral intermediate NMP kinases bring two nucleotides, such as AMP and ATP, together to facilitate the transfer of a phosphoryl group from one nucleotide to the other (creating two ADP). The enzyme positions the adenosine triphosphate (ATP) such that the gamma phosphate group is placed adjacently to the phosphate group of the NMP kinase. This facilitates the transfer of the phosphate between the two molecule. In aspartate ammonia lyase, a deprotonated serine sidechain performs a nucleophilic attack on a carbonyl carbon of the substrate. An active site histidine abstracts a proton from a substrate, making it more reactive, and then donates the proton back to the product. general acid/base catalysis catalysis by approximation metal-ion catalysis covalent catalysis

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter23: Fatty Acid Catabolism

Section: Chapter Questions

Problem 21P: Using the ActiveModel for enoyl-CoA dehydratase, give an example of a case in which conserved...

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Mechanisms of catalysis : 2.1 Acid-base catalysis summary + example 2.2 Electrostatic catalysis summary + example 2.3 Covalent catalysis summary + example 2.4 Enzymen catalysis summary 2.5 Mechanism of chymotrypsin summary. These mechanisms involve several of the above-mentioned catalyses. In these summaries, do not just draw a diagram of the proposed mechanisms. It is more important to understand which reaction steps involve what kind of catalysis and how these help to reduce the activation energy needed for the reaction (e.g. a step in the reaction mechanism could be electrostatic catalysis to stabilise the transitions state) 2.6 Mechanism of lysozyme summary. These mechanisms involve several of the above-mentioned catalyses. In these summaries, do not just draw a diagram of the proposed mechanisms. It is more important to understand which reaction steps involve what kind of catalysis and how these help to reduce the activation energy needed for the reaction (e.g.…
During chymotrypsin-mediated catalysis, which of the following statements is true? Select any/all answers that apply. A. A basic (positively-charged) side chain of the substrate polypeptide sits within the oxyanion hole of the enzyme. B. A basic (positively-charged) side chain of the substrate polypeptide sits within the specificity pocket of the enzyme. C. Ser195 hydrogen-bonds with the backbone carbonyl group of the substrate polypeptide within the oxyanion hole of the enzyme. D. All three residues that comprise the catalytic triad of the enzyme interact directly with the substrate polypeptide chain. E. Both covalent catalysis and acid-base catalysis occur.
Shown below is a proposed mechanism for the cleavage of sialic acid by the viral enzyme neuraminidase. The kcat for the wild-type enzyme at pH =6.15, 37 °C is 26.8 s-1.(a) Describe the roles of the following amino acids in the catalytic mechanism: Glu117, Tyr409, and Asp149. List all of the following that apply:general acid/base catalysis (GABC), covalent catalysis, electrostaticstabilization of transition state.(b) Based on the information shown in the scheme, would you expect mutation of Glu 117 to Ala to have a greater effect on KM or kcat?(c) For the R374N mutant at pH = 6.15, 37 °C, kcat is 0.020 s-1, and KMis relatively unaffected. Based on this result, it seems that R374 is morecritical for catalysis than for substrate binding. Explain how R374 stabilizesthe reaction transition state more than the substrate (i.e., what feature of this reaction would explain tighter binding to the transition state vs. substrate?).
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The formation of a Schiff base in the enzymatically catalyzed decarboxylation of acetoacetate is an example of— electrostatic catalysis. proximity catalysis. covalent catalysis. transition-state catalysis. concerted acid/base catalysis.
Look at the synthesis of citryl CoA by citrate synthase in the figure. Which of the 4 general catalytic mechanisms are present? Catalysis by approximation Covalent Catalysis General Acid-Base Catalysis Metal Ion Catalysis
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An enzyme catalysed reaction has a Km of 8 mM and a Vmax of 13 nM.s-1. Use the Michaelis-Menten equation to calculate the reaction velocity when the substrate concentration is 18 mM.