Question

Please help with a-e

The data below describes the synthesis of PGG2, a prostaglandin precursor molecule, by a COX enzyme in the presence and absence of ibuprofen. Ibuprofen has a molecular weight of 206 g/mol. (Please see photo for data chart)

a. Determine the Vmax and KM of the enzyme with no ibuprofen.

b. Determine the Vmax and KMapparent of the enzyme in the presence of ibuprofen.

c. Based on your answers to a and b, what type of inhibition does ibuprofen exert on prostaglandin synthesis?

d. Calculate α for ibuprofen.

e. Calculate a KI value for ibuprofen.

4.(11 points) The data below describes the synthesis of PGG2, a prostaglandin precursor molecule, by a COX enzyme in the presence and absence of ibuprofen. Ibuprofen has a molecular weight of 206 g/mol. Arachidonic acid Rate of formation of PGG2 Rate of formation of PGG2 concentration (MM) (mM/min) with 10 mg/mL ibuprofen (mm/min) 23.5 16.7 1.0 32.2 25.3 1.5 36.9 30.5 41.8 37,0 3.5 44.0 38.9 0.5

Answer 1

Part a:

I am going to use exel2007 to calculate the exercise because I must calculate 1/{arachidonic acid], 1/V_max out of ibuprofen and with ibuprofen.

Vmax PGGE2 formation (mm/min) 23,5 [Arachidonic acid] (mm) 2,000 1,000 0,667 0,400 0,286 32,2 1/Vmax PGGE2 formation (min/mm) 0,043 0,031 0,027 0,024 0,023 Vmax PGGE2 formation with ibuprofen (mm/min) 1/Vmax PGGE2 formation with ibuprofen (min/mm) 16,7 0,060 25,3 0,040 30,5 0,033 37,0 0,027 38,9 0,026 36,9 41,8 44,0

0,065 0,060 y = 0,0202x + 0,0194 R2 = 0,9993 0,055 0,050 0,045 1/Vmax 0,040 Out of ibuprofen I with ibuprofen Lineal (with ibuprofen) Lineal (Out of ibuprofen) y = 0,0116x+0,0194 R2 = 0,9999 0,035 0,030 0,025 0,020 0,000 0,500 2,000 2,500 1,000 1,500 [Arachidonic acid)-1 (mM-1)

The Michaelis Menten constant is the arachidonic acid concentration when the reaction rate be maximal. In this exercise is the inverse if the origin ordenate. y=mx+b. There is the value of y when x is equal to zero. V_max=1/b

Vmar = 7 = 0.0194 min 51.5464 MM min

The value of m in y=mx+n is equal to

KM m Var

Units en on Isla mi

KM 0.0116min = Var

KM 0.0116min = 21 51.5464 mm

0.0116min * 51.5464" KM min

0.5979m M = KM

K_M=0.5979mM

Part b

I must use 1/V_max    with ibuprofen to calculate V_max with its b. Because b is just the same as part a, V_max=51.5464mM/min

Then, I must use m part in the equation y=mx+b in the ibuprofen`s measurements

m=0.0202min

т = КМарр — Vinar

ΚΜαΡΡ. 0.0202min =- 51.5464

0.0202min * 51.5464 - = KMapp min

1.0412m M = K Mapp

K_Mapp=1.0412mM

Part c:

The kind of inhibition that ibuprofen does over prostaglandin synthesis is a competitive inhibition because its upper reaction rate remains the same while K_M is increasing.

Part d: To calculate $\alpha$ I have to calculate
(1+ ki
in which $\frac{[I]}{K_{I}}$ is $\alpha$

Knapp = (1+) * KM

K Mapp 1.0412mM/ 0.5979m M = KM

(1 + = 1.7414 KI

-= 1.7414-1=0.7414 = a Ki

Part e:

To calculate K_I without [I] I must determine equilibrium dissociation of ibuprofen

1.7414 = 1+

0.7414=