11.Quantitative Relationships between Rate Constants to Calculate Km, KineticEfficiency (kcat/Km) and Vmax - II Triose phosphate isomerase catalyzes theconversion of glyceraldehyde-3-phosphate to dihydroxyacetone phosphate.Glyceraldehyde-3-P dihydroxyacetone-PThe Km of this enzyme for its substrate glyceraldehyde-3-phosphate is 1.8 x 10-5 MWhen [glyceraldehydes-3-phosphate] = 30 μM, the rate of the reaction, v, was82.5 μmol mL-1 s-1.a. What is Vmax for this enzyme?b. Assuming 3 nm/mL of enzyme was used in this experiment (E total = 3nm/mL)for this enzyme?c. What is the catalytic efficiency (kcat/km) for triose phosphate isomerase?d. Does this enzyme reach catalytic perfection?

Kinetic parameters are Km and Vmax. They are used to determine the efficiency of an enzyme. Km is…

Answered: 11. Quantitative Relationships between…

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter18: Glycolysis

Section: Chapter Questions

Problem 18P: Distinguishing the Mechanisms of Class I and Class I Aldolases Fructose bisphosphate aldolase in...

See similar textbooks

Similar questions

1. The enzyme glutamate dehydrogenase is important in the breakdown of amino acids to produce NH4+. High levels of NH4+ in the body are toxic, and for this reason it is used to form urea to be excreted in the urine. Using the information provided, calculate the delta G knot prime and the Keq value at 298K for the oxidation of glutamate catalyzed by glutamate dehydrogenase. (Constants: R=8.3J/degree.mol, F=96.1kJ/V.mol) How to identify the final and initial reactions in a group of redox reactions and do we reverse the reduction reaction if the question asks for oxidation?
1. The enzyme glutamate dehydrogenase is important in the breakdown of amino acids to produce NH4+. High levels of NH4+ in the body are toxic, and for this reason it is used to form urea to be excreted in the urine. a) Using the information provided, calculate the delta G knot prime and the Keq value at 298K for the oxidation of glutamate catalyzed by glutamate dehydrogenase. (Constants: R=8.3J/degree.mol, F=96.1kJ/V.mol) b) Given the reaction above, why would high levels of NH4+ be toxic? c) Given the reaction above, explain how a high concentration of gutamate inside the cell would affect energy production. Be sure to be specific.
The catalytic efficiency of many enzymes depends on pH. Chymotrypsin, which has a well-known catalytic mechanism, shows a maximum value of kcat/Km at pH 8.0. A) Draw a pH curve of chymotrypsin activity over the pH range of 5 to 10 and briefly explain the rationale within the context of catalysis for your depiction. In particular, note how kcat and Km may change over this pH range. B) Enzymes of the a-amylase family catalyze a reaction by forming a covalent intermediate analogous to chymotrypsin, but to a conserved aspartate residue. Illustrate a catalytic mechanism containing a tetrahedral intermediate for a glycogen debranching enzyme based upon its potential membership in the a-amylase family. (don’t need to draw a whole glycogen)
Proline racemase catalyzes the conversion between L-proline and D-proline. The Km and kcat for this reaction are 0.15 M and 550/sec respectively. If the enzyme concentration is 1.45 X 10-5 mmole/ml what is the Vmax of this reaction?
1. Sulfanilamide, a sulfur drug, acts as an antibiotic. Explain its mechanism of action in the context of enzyme inhibition. 2. Methotrexate is used in cancer chemotherapy. Explain how this compound works by elaborating on the type of enzyme inhibition involved for its action. 3. For the following aspartate reaction in the presence of inhibitor, Km = 0.00065 M. Determine Vmax in both reactions and in the reaction without inhibitor, the Km. Identify whether the inhibition is competitive, non-competitive or uncompetitive. ( see attached picture ) 3a. how I and S bind to the E as shown by the Lineweaver Burk plot. 3b. the significance of the following obtained values for Km and Vmax. 3c. effect in slope and x-intercept
A new drug, Proinebrium, that reduces Kcat (Ki = 2.0 uM) has been developed to treat ethylene glycol poisoning. (1) What concentration of Proinebrium is required to achieve 50% inhibition of ethylene glycol metabolism by alcohol dehydrogenase when the concentraion of ethlyene glycol in the blood is 50 uM?
ATP is a (+) allosteric effector, and CTP is a (-) allosteric effector of theenzyme ATCase. Both of these heterotropic effectors bind to the regulatorysubunits on ATCase. The substrates of ATCase, aspartate and carbamoylphosphate, bind the enzyme active site with positive cooperativity (i.e.,they exert a “+” homotropic effect on activity). As the concentrations ofthe substrates change from values where [S] ≪ KM to values where [S] issaturating ([S]≫ KM), how will the binding constants for each of the twoallosteric effectors change? In other words, does ATP bind ATCase withhigher affinity when [S] is low or high? Does CTP bind ATCase with higheraffinity when [S] is low or high?
Many enzymes obey simple Michaelis–Mentenkinetics, which are summarized by the equationrate = Vmax [S]/([S] + Km)where Vmax = maximum velocity, [S] = concentration ofsubstrate, and Km = the Michaelis constant.It is instructive to plug a few values of [S] into theequation to see how rate is affected. What are the rates for[S] equal to zero, equal to Km, and equal to infinite concen-tration?
Recall that phosphonacetyl L - aspartate (PALA) is a potent inhibitor of ATCase because it mimics the two physiological substrates. However, in the presence of substrates, low concentrations of this unreactive bisubstrate analog increase the reaction velocity. On the addition of PALA, the reaction rate increases until an average of three molecules of PALA are bound per molecule of enzyme. This maximal velocity is 17-fold greater than it is in the absence of PALA. The reaction rate then decreases to nearly zero on the addition of three more molecules of PALA per molecule of enzyme. Why do low concentrations of PALA activate ATCase?
The muscle isozyme of lactate dehydrogenase is inhibited by lactate.Steady-state kinetic analysis yielded the following data, with lactate eitherabsent or present at a fixed concentration. (a) Pyruvate is the substrate whose concentration is varied in one plot, NADH in the other. Identify each. Use an arrow and the appropriate letter (b,c,d,ore) to identify each of the following. (b) Reciprocal of Vmax for the uninhibited enzyme. (c) The line representing data obtained in the presence of lactate acting as a competitive inhibitor with respect to the variable substrate. (d) The line representing data obtained in the presence of lactate acting as a noncompetitive inhibitor with respect to the variable substrate. (e) Reciprocal of KM in the presence of lactate acting as a competitive inhibitor. (f) If KM for NADH is 2 x 10-5 M, then which of the following is the most appropriate NADH concentration to use when determining KM for pyruvate: 10-7 M, 10-6 M, 10-5 M, 10-4 M, or 10-3 M?M
Many enzyme -catalyzed reactions are consistent with a modified version of the Michaelis -Menten mechanism in which the second step is also reversible. For this mechanism obtain an expression for the rate of formation of product and find its limiting behavior for large and small concentrations of substrate using steady state approximation
Phosphonacetyl-L-aspartate (PALA) is a potent inhibitor of aspartate transcarbamoylase because itmimics the two physiological substrates of the enzyme. However, in the presence of substrates, lowconcentrations of PALA increase the reaction rate of aspartate transcarbamoylase. Explain this result.

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

SEE MORE TEXTBOOKS