Experiment IV: Effect of pH on the Rate of Enzyme Reaction
6. In this experiment, was the enzyme denatured or just slowed
down at any of the pH values tested? What is the evidence?
Materials for Experiment IV
Five test tubes
Test tube rack
Disposable pipettes
Potato extract
Deionized water
Water bath, 37 degrees Celsius (°C)
0.1 molar (M) sodium hydroxide (NaOH)
0.1 M hydrochloric acid (HCl)
pH paper
Procedure for Experiment IV
Five test tubes were taken and labeled...
To the nearest hundredths, what is the pH at the end of an
enzyme-catalyzed reaction if it were carried out in a 0.1 M buffer
initially at pH 6.65, and 0.006 M of acid (H+) was produced during
the reaction? (The buffer used was a polyprotic acid of the general
form: H3A; the three pKas of this polyprotic acid are
2.11, 6.65, and 11.33.)
To the nearest hundredths, what is the pH at the end of an
enzyme-catalyzed reaction if it were carried out in a 0.1 M buffer
initially at pH 6.73, and 0.004 M of acid (H+) was produced during
the reaction? (The buffer used was a polyprotic acid of the general
form: H3A; the three pKas of this polyprotic acid are 2.17, 6.73,
and 11.27.)
To the nearest hundredths, what is the pH at the end of an
enzyme-catalyzed reaction if it were carried out in a 0.1 M buffer
initially at pH 6.73, and 0.004 M of acid (H+) was produced during
the reaction? (The buffer used was a polyprotic acid of the general
form: H3A; the three pKas of this polyprotic acid are
2.17, 6.73, and 11.27.)
The effect of an inhibitor on an enzyme was tested and the
experiment gave the results below. Plot on Excel the data using a
double-reciprocal plot (Lineweaver-Burke), determine Km
and Vmax of the no inhibitor and each type of inhibitor
and the type of inhibition that is occurring.
[S] µM V
(µmol/min) V (µmol/min) V (µmol/min)
with 0.0 nM with 25 nM
with 50 nM
Inhibitor
Inhibitor
Inhibitor
______
___________ ___________ ___________
0.4
0.22
0.21
0.20...
What kind of an effect does an enzyme have on the rate of the
forward and reverse reactions, the energy of the products and
reactants and the energy of the transition state?
1. (3%) You measure the initial rate of an enzyme reaction as a
function of substrate concentration in the presence and absence of
an inhibitor. The following data are obtained: [S] V0 –Inhibitor
+Inhibitor 0.0001 33 17 0.0002 50 29 0.0005 71 50 0.001 83 67 0.002
91 80 0.005 96 91 0.01 98 95 0.02 99 98 0.05 100 99 0.1 100 100 0.2
100 100
a) What is the Vmax in the absence of inhibitor?
b) What is...
3. a. What effect does temperature have on the reaction rate of
oxalic acid and permanganate? b. Will temperature have an effect on
the equilibrium constant of this reaction?
25) Am enzyme-catalyzed reaction proceeds at a faster
rate than an uncatalyzed reaction because the enzyme lowers the
difference in free energy between the reactants and the
products.
a. True
b. False