Are the given examples representative of acid-base catalysis, covalent catalysis, or metal ion catalysis? Glu R HN R' Enzyme substrate complex Glu R HN R' Oe Zn2+ Tetrahedral intermediate 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, then donates the proton back to the product. general acid-base catalysis covalent catalysis metal ion catalysis

Are the given examples representative of acid-base catalysis, covalent catalysis, or metal ion catalysis? Glu R HN R' Enzyme substrate complex Glu R HN R' Oe Zn2+ Tetrahedral intermediate 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, then donates the proton back to the product. general acid-base catalysis covalent catalysis metal ion catalysis

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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Which of the following is false regarding Serine Proteases? O They employ general acid-base catalysis They contain a catalytic Triad of His, Ser, and Asp residues They employ metal ion catalysis O They cleave simple organic ester bonds near larger residues
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
Given the active site diagram below, indicate the mechanism(s) of catalysis. 5 HO OH HN OH ΝΗ *HN ΝΗ Zn²+ Acid-base, Metal ion 3 Metal ion, By Approximation Metal ion Acid-Base, By Approximation Acid-base
Which of the following statements about ribozyme catalytic residues is INCORRECT? General acid catalysis requires the standarde nucleotide exchangeable proton acidities (represented by pKa values). Ribozymes work by lowering the AG‡ through transition state stabilization without changing the overall AG of the reaction. Some ribozymes cleave phosphodiester bonds, and like proteases, can be autocatalytic. There are fewer known classes of mammalian ribozymes than mammalian enzyles.
Shown below is a substrate for a Trypsin. Draw the mechanism for this serine protease using the artificial substrate. Be sure to draw the catalytic triad, and show the role of the oxyanion hole. Draw the complete structure of every intermediate and product and PUSH ARROWS!!!!! Do not abbreviate structures using R and R' H₂N _N_CH. сно CH₂ CH₂ CH₂ NH d=19H₂ NH₂ O CH- H₂C HN O CH
The use of co-factors in catalysis: Cofactors Cofactor Origin: Structure: Catalytic role: Nicotinamide nucleotides Flavin nucleotides Adenosine phosphates Coenzyme A Biotin Coenzyme B12 Summaries the characteristics of co-factors using this table. Use both the textbook and other online sources such as Wikipedia to find the information. Under origin, report the precursor molecule e.g. “niacin” and also try to find the Vitamin X name for each compound, e.g. “Vitamin B3”. Under structure, identify the unique structural properties that allow each cofactor to perform the function it does Under catalytic role, indicate for which reactions are each of the cofactors important
1. Please fully explain (use illustrate where appropriate) the Modes of Enzyme Catalysis exemplified by the serine protease: Chymotrypsin. In your answer discuss employing the illustration whenever possible: the overall reaction mechanism, stability of the reaction transition state, proximity and orientation effects, acid-base catalysis, and covalent catalysis. (c) (0) Ap Asp Toe His Asp 10 C-N bond cleavage HN Ho Ser Ger Binding of substi 196 Ser Gly alto video LBHB NH Sere HAR Proton donation by H (h) Fel of amino product yest OHN Hig Ser Ap (0) Formation of covalent (ES) Alp Me complex Serios
Why is the covalent intermediate of elastase stable at low pH? The catalytic histidine cannot act as general acid when protonated. O The catalytic histidine cannot act as a general base when protonated. The catalytic serine cannot form a covalent bond to substrate if the pH is below 7.4. O The catalytic serine cannot preferentially form a hydrogen bond with the catalytic histidine at acidic pH, causing these residues to shift out of their catalytically optimal positions.
During chymotrypsin-mediated catalysis, which of the following statements is true? Select any/all answers that apply. O A. A basic (positively-charged) side chain of the substrate polypeptide sits within the oxyanion hole of the enzyme. O B. A basic (positively-charged) side chain of the substrate polypeptide sits within the specificity pocket of the enzyme. O C. Ser195 hydrogen-bonds with the backbone carbonyl group of the substrate polypeptide within the oxyanion hole of the enzyme. O D. All three residues that comprise the catalytic triad of the enzyme interact directly with the substrate polypeptide chain. O E. Both covalent catalysis and acid-base catalysis occur.
The enzyme which catalyzes the reaction below belongs to which enzyme classification? Н.С— ОН HC=0 C=0 Н-С—ОН H,C-0-P-o- || H,C –0-P-0- O Transfera Hydrolase Isomerase Oxidoreductase
Shown below is a substrate for a Elastase. CH, HN NH NH, Draw the mechanism for this serine protease using the artificial substrate. Be sure to draw the catalytic triad, and show the role of the oxyanion hole. Draw the complete structure of every intermediate and product and PUSH ARROWS!
In serine protease catalytic triad mechanism, the first and second products that leaves the active site are Carboxylic acid and amide respectively Amide and carboxylic acid respectively Ester and amide respectively Carboxylic acid and ester respectively