End product inhibition of multistep pathways is a major mechanism for cellular r
ID: 976010 • Letter: E
Question
End product inhibition of multistep pathways is a major mechanism for cellular regulation. In this process the, product of the last enzyme inhibits the substrate of the last enzyme Product of the first enzyme inhibits the last enzyme in the pathway First enzyme in the pathway is inhibited when ATP concentrations are depleted Product of the last enzyme inhibits the first enzyme in the pathway End product causes an intermediate enzyme to form a different product and cause a branch in the pathway. Lineweaver-burk (double reciprocal) analysis allows for the determination of V_max only K_m only V_max and K_m Neither V_max, K_m The reaction product In the mechanism of action of chymotrypsin, serine 195 Functions as a nucleophilic reagent Functions as an electrophilic reagent Forms a Schiff base intermediate with part of the substrate Forms anamide-chymotrypsin intermediate Two of the above Which of the following terms best describes the effect that CTP has on the enzyme aspartate carbamoyl transferase Feedback inhibitor Partial proteolysis Zymogen activation An enzyme cascade The K_m is The time for half of the substrate to be converted to product The time for all of the substrate to be converted to product The (S) that gives half of the maximum reaction rate The (S) that gives the maximum reaction rate The [P] that is produced when the enzyme is saturated with the substrateExplanation / Answer
17) The product of the last reaction in the end-product inhibition inhibits the enzyme that catalyses the first reaction of the pathway.The pathway involves non-competitive inhibitors.
Answer (d)
18) A plot of 1/V0 versus 1/[S], called a Lineweaver-Burk or double-reciprocal plot, yields a straight line with an intercept of 1/Vmax and a slope of KM/Vmax.
Answer (c)
19) Hydrogen bond occurs between the Schiff nitrogen on histidine-57 and the oxygen side-chain of serine-195 and the hydroxyl group on serine-195 performs a nucleophilic attack on the carbonyl carbon of an aromatic amino acid.
Answer (e) {a and c both are correct answers.}
20) Aspartate transcarbamoylase or ATCase is used to catalyze the first step of the pyrimidine biosynthetic pathway.Cytidine triphosphate CTP decreases catalytic velocity.
Answer (a) Feedback inhibitor
21) Km = 1/2 Vmax A small Km indicates that the enzyme requires only a small amount of substrate to become saturated.
Answer (e)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.