5. E. coli ribonuclease H1 is an enzyme that catalyzes the hydrolysis of phosphodiester bonds in RNA. Its proposed mechanism involves a 'carboxylate relay,' as shown below. His124 Asp70 || -HN-CH-C -HN-CH-C- CH2 CH2 c=0 RNA substrate HN H. H. (1) Fill the blanks. In the reaction scheme above, His124 acts as a ( ). The purpose of this relay system is to deprotonate the water molecule (II) so that it becomes a better ( :0

5. E. coli ribonuclease H1 is an enzyme that catalyzes the hydrolysis of phosphodiester bonds in RNA. Its proposed mechanism involves a 'carboxylate relay,' as shown below. His124 Asp70 || -HN-CH-C -HN-CH-C- CH2 CH2 c=0 RNA substrate HN H. H. (1) Fill the blanks. In the reaction scheme above, His124 acts as a ( ). The purpose of this relay system is to deprotonate the water molecule (II) so that it becomes a better ( :0

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter6: Energy, Enzymes, And Biological Reactions

Section: Chapter Questions

Problem 8TYK: Which of the following statements about the allosteric site is true? a. The allosteric site is a...

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2 Please draw the arrow-pushing mechanism to create the polyketide backbone chain of TYLOSIN. If two or more extension rounds are exactly the same, you do not need to draw them more than once. However, please clearly indicate which steps are being repeated. Please draw the complete “business end” of any cofactors you use in a step
1. A certain polypeptide was treated with trypsin and yielded the following Fragments: Leu-Glu Gly-Tyr-Asn-Arg Gln-Ala-Phe-Val-Lys The same polypeptide was treated with chymotrypsin and yielded the following fragments: Gln-Ala-Phe Asn-Arg-Leu-Glu Val-Lys-Gly-Tyr What is the amino acid sequence of this polypeptide? Instructions Make use of the table below to determine the sequence of the mystery protein.
Christian Anfinsen showed that the enzyme Ribonuclease (RNase) is completely inactivated at high concentrations of beta mercaptoethanol (BME). When BME is removed, it restores only approximately 1% of RNase activity. When a very low concentration of BME is added back to RNase, its activity is restored to nearly 100%. Why? a Low concentrations of BME causes disulfide bonds to break, but they randomly reform. b High concentrations of BME disrupt all disulfide bonds, which inactivates the enzyme. At low concentrations all of the disulfide bonds reform and BME acts as a cofactor for the enzyme. c The enzyme is only active when an intermediate number of disulfide bonds exists. which is achieved only at low concentrations of BME. d The low concentration of BME allows the majority of the proteins to adopt their most stable form, which is the active form.
Which of the following statements about the allosteric site is true? a. The allosteric site is a second active site on a substrate in a metabolic pathway. b. The allosteric site on an enzyme can allow the product of a metabolic pathway to inhibit that enzyme and stop the pathway. c. When the allosteric site of an enzyme is occupied, the reaction is irreversible and the enzyme cannot react again. d. An allosteric activator prevents binding at the active site. e. An enzyme that possesses allosteric sites does not possess an active site.
1 is there a positive or negative entropy change in the first step of histidine synthesis? 2 how many 1-carbon transfer reactions occur in the pathway? 3 how many transamination reactions occur in the pathway ? 4 in purine and pyrimidine synthesis , ________ from the_______pathway is activated by _______ 5 which molecule functions as both an amino group donor and acceptor in this pathway ? 6 during the degradation of histidine, the amino acid group will give rise to _______ while the carbon skeleton will give rise to _______ does not need energy. 7 to which chemical messenger will the decarboxylation of histidine give rise?
1- Biochemist Erwin Chargaff was the first to note that, in DNA, [A] = [T] and [G] = [C], equalities now called Chargaff’s rule. With the use of this rule, determine the percentages of all the bases in a DNA molecule which contains 35% thymine. Explain. 2- Similar equalities (i.e. [A]=[U] and [G]=[C]) are however not observed in RNA molecules. Explain the structural differences which dictate why Chargaff rule does not apply to RNA polynucleotides.
mutate all of your D-form amino acids in your peptidoglycan peptide side chains to L forms. What have just done to your peptidoglycan? • A. You prevent lysozyme from being able to work • B. You prevent NAM and NAG from linking together C. You have made it susceptible to degradation by proteases • D. You prevent it from being flipped from the cytoplasm across the plasma membrane O E. Nothing, there is no difference between the L and D forms of amino acids
The following data describe the catalysis of cleavage of peptide bonds in small peptides by the enzyme UTSAse (the arrow indicates the peptide bond cleaved in each case). Substrate Km(mM) kcat(s-1) PAPA↓G 4.0 26 PAPA↓A 1.5 37 PAPA↓F 0.64 18 what features of amino acid sequence dictate the specificity of the proteolytic cleavage? Large hydrophilic R-groups Large hydrophobic R-groups Neutral R-groups Small hydrophilic R-groups Large hydrophobic R-groups Negatively charged R-groups Positively charged R-groups
1. Why does a cell use deoxyribonuclease?
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When performing his experiments on protein refolding, Christian Anfinsen obtained a quite different result when reduced ribonuclease was reoxidized while it was still in 8 M urea and the preparation was then dialyzed to remove the urea. Ribonuclease reoxidized in this way had only 1% of the enzymatic activity of the native protein. Why were the outcomes so different when reduced ribonuclease was reoxidized in the presence and absence of urea?
1. The figure above shows some of the more common modifications, such as phosphorylation (1), acetylation or methylation (2), adding sugars or lipids (3,4), or adding another polypeptide (5). There are many other possibilities as well.Find and label each of these on the diagram. How might these modifications affect the protein?