Videos
Interpretation:
About the chemistry of dTMP synthesis and the substrate-binding site of thymidylate synthase.
Concept introduction:
Thymidylate synthetase is an accelerator that catalyzes the conversion of deoxyuridine monophosphate (dUMP) to
Answer to Problem 15P
The balanced reaction is:
Explanation of Solution
The following are the reactions concerned within the conversion of UMP and
Taking away like products and reactants.
This leaves us with a net reaction.
The charged aspect chains of essential amino acid are wont to pull in negatively charged groups as seen within the catalyst thymidylate synthase. Note that Arg23 and Arg218 are on separate subunits than Arg178and Arg179.
The balanced reaction is:
Want to see more full solutions like this?
Chapter 26 Solutions
Biochemistry
- The enzymatic activity of lysozyme is optimal at pH 5.2 and decreases above and below this pH value. Lysozyme contains two amino acid residues in the active site essential for catalysis: Glu35 and Asp52. The pK value for the carboxyl side chains of these two residues are 5.9 and 4.5 respectively. What is the ionization state of each residue at the pH optimum of lysozyme? How can the ionization states of these 2 amino acid residues explain the pH-activity profile of lysozyme?arrow_forwardEquation 7a of the text, (Umax/KM1) [S] (v'max/KM2) [P] 1+ [S]/KM1 + [P]/KM2 - gives the expression for the rate of formation of product by a modified version of the Michaelis-Menten mechanism in which the second step is also reversible. Derive the expression and find its limiting behaviour for high and low concentrations of substrate.arrow_forwardPropose a mechanism for the conversion of Sadenosylmethionine into 1-aminocyclopropane-1-carboxylate (ACC) by ACC synthase, a PLP enzyme. What is the other product?arrow_forward
- Phosphoglycerate kinase shows induced fit resulting from the binding of both substrates to form the closed catalytic conformation. Maintainence of the closed conformation depends on the formation of a salt bridge between R62 and D200. What would be the effect of the mutation of D200 to the unusual amino acid shown below? Explain.arrow_forwardWhat would be the effect on the activity of phosphofructokinase of the mutation of Asp103 to the unusual amino acid shown below? Explain in terms of actual structures of the side chains of Asp and this unusual amino acid.arrow_forward. The mechanism for lysozyme cleavage of its polysaccharide substrate requires Glu35 in its nonionized form, whereas the nearby Asp52 must be ionized (see the figure below). The pK values for the side-chain carboxyl groups on the two amino acids in solution are virtually identical. a) How can one carboxyl group be charged and the other uncharged in the active site of lysozyme? b) The pH optimum for lysozyme is about 5. Why do you suppose that the activity decreases above and below this optimum? Glu3s NAG Asp52 0-H Glu35 -C Asp52 tri-NAG NAGarrow_forward
- help with part a and b pleasearrow_forwardSynthesis of the purine nucleotides AMP andGMP proceeds by a branched pathway starting with ribose5-phosphate (R5P), as shown schematically in FigureQ3–4. Using the principles of feedback inhibition, proposea regulatory strategy for this pathway that ensures an ade-quate supply of both AMP and GMP and minimizes thebuildup of the intermediates (A–I) when supplies of AMPand GMP are adequate.arrow_forwardEscherichia coli Fpg protein is responsible for removing damaged DNA base pairs such as C8-oxoguanine (8-oxoG). The catalytic mechanism is believed to involve the formation of a transient Schiff base intermediate formed between DNA base the N-terminal proline residue. Draw the structure of PTH-derivative that is formed after Fpg is subjected to one cycle of Edman degradation.arrow_forward
- Residue Asn 204 in the glucose binding site of hexokinase IV was mutated, in two separate experiments, to either Ala or Asp. The Asn → Ala mutant had a KM nearly 50-fold greater than the wild-type enzyme, and the Asn → Asp mutant had a 140-fold greater KM value than the wild-type enzyme. These mutations impact the intermolecular interactions between the enzyme and the glucose substrate.The amide functional group of the Asn side chain can form with the hydroxyl groups of the glucose substrate and can potentially function as either a . The methyl group of Ala cannot participate in hydrogen bond formation, which explains the in glucose affinity as indicated by the higher KM for the mutant enzyme. The side chain of Asp could potentially serve as a , but…arrow_forwardResidue Asn 204 in the glucose binding site of hexokinase IV was mutated, in two separate experiments, to either Ala or Asp. The Asn → Ala mutant had a KM nearly 50-fold greater than the wild-type enzyme, and the Asn → Asp mutant had a 140-fold greater KM value than the wild-type enzyme. These mutations impact the intermolecular interactions between the enzyme and the glucose substrate.The amide functional group of the Asn side chain can form (dipole-dipole interactions, hydrodgen bonds, London Dispersion Interactions, or Ion-Dipole Interactions) with the hydroxyl groups of the glucose substrate and can potentially function as either a (hydrogen bond donor and/or acceptor, hydrogen bond donor, or hydrogen bond acceptor) . The methyl group of Ala cannot participate in hydrogen bond formation, which explains the (increase or decrease)…arrow_forwardThe specific activity of a pure preparation of pyruvate kinase (PK) assayed in the direction of pyruvate formation (forward direction) is 220 U/mg at 25 C and at pH 7.5. This form of PK is a homotetramer (MW 240,000) with one active site per subunit. What is the kcat for PK in the forward direction?arrow_forward
BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning