Question

In: Biology

1) The enzyme prostaglandin synthase uses aracadonic acid as the substrate and produces product PGG2. If...

1) The enzyme prostaglandin synthase uses aracadonic acid as the substrate and produces product PGG2. If 10mM Ibuprofin inhibits this enzyme as is seen in the 3rd column..

[S](mM) PGG2(Vo mM/min) I (Vo mM/min)

0.5 23.5 16.67

1.0 32.2 25.25

1.5 36.9 30.49

2.5 41.8 37.04

3.5 44.0 38.91

What is the Ki' ? (THE ANSWER IS UNDEFINED, EXPLAINS AND SHOW YOUR WORK PLEASE)

Expert Solution

1/Vo = (Km/Vmax) 1/S+ 1/Vmax

Comparing this equation with Y=aX + c

where a is the slope and c is the intercept

so V max = 1/intercept

For inhibited reaction = 1/0.0116 = 82.20 mM/min

For X inhibitor = 1/0.0205 = 48.78 mM/min

Km/Vmax is equal to slope

Km = Vmax * slope

For enzyme

Km = 82.2 *0.0194 = 1.59 mM

For X compound

48.78* 0.0191 =0.931 mM

In presence of inhibitor, both Km and Vmax are decreasing so the inhibition is uncompetitive inhibition.

For uncompetitive inhibition

Kapp = Km / (1+ I/Kapp)

0.931 = 1.59 / (1+ I / 0.931)

0.931 = 1.59 / (0.931 +I) /0.931

0.931 +I / 0.931 = 1.59/0.931

0.931 + I = 1.59

I = 1.59 - 0.931

I = 0.66 mM

gladiator answered 2 years ago

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