Acetylsalicylic acid (ASA) is the active compound of aspirin. It binds the active site of COX-1 (Cyclooxygenase1) where it is initially processed by the normal catalytic mechanism generating a chemically reactive intermediate that inactivates the enzyme through covalent modification. Hence, aspirin acts as: Select one: a. Suicide inactivator? O b. Transition state analogue? O c. Substrate analogue? O d. Group specific reagent?

Acetylsalicylic acid (ASA) is the active compound of aspirin. It binds the active site of COX-1 (Cyclooxygenase1) where it is initially processed by the normal catalytic mechanism generating a chemically reactive intermediate that inactivates the enzyme through covalent modification. Hence, aspirin acts as: Select one: a. Suicide inactivator? O b. Transition state analogue? O c. Substrate analogue? O d. Group specific reagent?

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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Using the ActiveModel for enoyl-CoA dehydratase, give an example of a case in which conserved residues in slightly different positions can change the catalytic rate of reaction.
When enzyme solutions are heated, there is a progressive loss of catalytic activity over time due to denaturation of the enzyme. A solution of the enzyme hexokinase incubated at 45 °C lost 50% of its activity in 12 min, but when incubated at 45 °C in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 min. Suggest why thermal denaturation of hexokinase was retarded in the presence of one of its substrates.
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When enzyme solutions are heated, there is a progessive loss of catalytic activty over time due to denaturation of the enzyme. A solution of the enzyme hexokinase incubated at 45 degrees Celsius lost 50% of its activity in 12 minutes, but when incubated at 45 degrees Celsius in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 minutes. Suggest why thermal denaturation of hexokinase was retarded in the presence of one substrates.
In the scheme for enzymatic catalysed reaction proposed by Michaelis and Menten, the steps involve reversible formation of enzyme-substrate (ES) complex followed by conversion of the complex to the product (P). a) Derive the rate equation for enzymatic process. State an assumption made in this derivation. Terbitkan persamaan kadar tindak balas bagi proses enzim. b) By showing appropriate reaction mechanisms and rate equations, explain how enzyme catalytic reactions may be affected by competitive inhibition
What are the three key mechanisms and their associated features that are utilized by enzymes to catalyze reactions. Additionally, which two mechanims of the three you listed does the enzyme chymotrypsin use?
An enzyme catalyzes a reaction in which substrate A is cleaved into two products, P and Q. In the catalytic mechanism, the enzyme converts A to an covalently-bound reaction intermediate X and product P, P then desorbs from the enzyme, and in a second chemical step, the enzyme converts the intermediate X in the EX complex to the final product Q (in EQ), which then desorbs from the enzyme E. You discover two inhibitors of this enzyme, I and J. I is a competitive inhibitor of the substrate A, and has nearly double the molecular weight of J. On the other hand, J is a mixed inhibitor of enzyme E, and its inhibitory effect on Km / Vmax (the slope effect from the double reciprocal plot) is greater than that of 1 / Vmax (the intercept effect in a double reciprocal plot). That is Kis < Kii . At low pH, the conversion of EX to EQ is greatly slowed, kcat is decreased, and the intercept effect of inhibitor J is elevated, that is, the value of Kii is diminished. When a high, fixed concentration…
In the scheme for enzymatic catalysed reaction proposed by Michaelis and Menten, the steps involve reversible formation of enzyme-substrate (ES) complex followed by conversion of the complex to the product (P) a) Derive the rate equation for enzymatic process. State an assumption made in this derivation. b) By showing appropriate reaction mechanisms and rate equations, explain how enzyme catalytic reactions may be affected by competitive inhibition
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Which of the following is true under the following conditions: an enzyme displaying Michaelis-Menten kinetics where the enzyme concentration is 10 nM, the substrate concentration is 45 mM, and the Km is 50 µM? a) The enzyme has low catalytic efficiency for the substrate. b)The rate of catalysis is near half-maximal velocity. c)The enzymatic reaction is near maximal velocity. d)Halving the substrate concentration has little effect on the catalytic rate. e) There is not enough information provided.
An enzyme catalyzes a reaction in which substrateA is cleaved into two products, P and Q. In the catalytic mechanism, the enzyme converts A to a covalently-bound reaction intermediate X and product P, P then desorbs from the enzyme, and in a second chemical step, the enzyme converts the intermediate X in the EX complex to the final product Q (in EQ), which then desorbs from the enzyme E.You discover two inhibitors of this enzyme, I and J. I is a competitive inhibitor of the substrate A, and has nearly double the molecular weight of J. On the other hand, J is a mixed inhibitor of enzyme E, and its inhibitory effect on Km/ Vmax (the slope effect from the double reciprocal plot) is greater than that of 1 / Vmax (the intercept effect in a double reciprocal plot). That is Kis< Kii . At low pH, the conversion of EX to EQ is greatly slowed, kcat is decreased, and the intercept effect of inhibitor J is elevated, that is, the value of Kiiis diminished. When a high, fixed concentration of…