111 T-Mobile 12:42 PM Done 7 of 7 -SHUMSKAYA Activities and Due Dates Ch 6Homewo

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111 T-Mobile 12:42 PM Done 7 of 7 -SHUMSKAYA Activities and Due Dates Ch 6Homework-Enzymes 018 11:59 PM 15.4/17 Grade Print li Calculator of 15 Periodic Table emical reaction HAPPY -SAD Map he researchers begin to characterize the |in the first expenment, with at 7 nk, they find that the Vmaxis 2.37 M s1 Based on this experiment, what is the Koat for happyase"? (b) In another experiment with Ea at 2 nM and [HAPPY) at 35 iMthe researchers find that 523 nM s1 What is the measured Km of happyase for its substrate HAPPY? Number 33857-1 Further research shows that the purifled happyase used in the first two actualy oved from the contaminated with a reverstIe inhibitor called ANGER when ANGER . happyase* preparation, and the two experiments repeated, the measurors increased to 7.10 M s-1 and the measured Km in (b) is now 11.9 JM. For the inhibitor ANGER, calculate the values of a' and a Number Number Based on the information given above, what type of inhibitor is ANGER? competitive inhibitor inhbitor about uscareers privacy policy serms of use contact us help

Explanation / Answer

Ans. #a. Kcat = Vmax / [E]t

= 2.37 uM s-1 / 7 nm                                                ; [1 uM = 103 nM]

= (2.37 x 103 nM s-1) / 7 nM

= 338.57 s-1

Hence, Kcat for Happyase = 338.57 s-1

#b. The Vmax of a reaction mixture is always proportional to enzyme concentrations.

We have,        Vmax at [E] of 7 nM = 2.37 uM s-1

Have to calculate Vmax at [E] = 2 nM

Now,

            Vmax at [E] of 2 nM = Vmax at [E] of 7 nM x ([E] of 2 nM)

                                                = (2.37 uM s-1 / 7 nM E) x 3 nM E

                                                = 0.677 uM s-1

Hence, at [E] of 2 nM, the Vmax = 0.677 uM s-1 = 677.0 nM s-1

# Calculate Km using MM equation- Vo = Vmax [S] / (Km + [S])

Re-arranging the above equation-

            Km = (Vmax [S] / Vo) – [S]

Putting the values in above equation-

Km= (677 nM s-1 x 35 uM / 523 nM s-1) – 35 uM

Or, Km = 44.85 uM – 25 uM = 19.85 uM

Hence, Km of Happyase = 10.31 uM

#c. So far we have-

            Vmax (in presence of Anger, #a) = 2.37 uM s-1 = Vmax,app

Km (in presence of Anger, #b) = 10.31 uM = Km,app

Vmax (Inhibitor free) = 7.10 uM s-1

Km (Inhibitor free) = 11.9 uM

# Now, using the formula-

            a’ = Vmax / Vmax,app = Vmax (In presence of inhibitor)/ Vmax (Inhibitor free)

            Or, a’ = 7.10 uM s-1 / 2.37 uM s-1

            Hence, a’ = 3.00

# Now, using the formula-

            a = (a’ x Km,app) / Km = (3.00 x 10.31 uM) / 11.9 uM = 2.60

#d. Type of inhibitor:.

Both Vmax and Km are decreased by different factors (because a and a’ are different). Decrease in Vmax and Km by different factors in the characteristic of mixed inhibition.

Therefore, ANGRY is a mixed inhibitor.

# Note: In competitive inhibition, Vmax remains the same but Km is increased.

In uncompetitive inhibition, both the Km and Vmax are decreased by same factor (i.e. a = a’).

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