Question

4. The following data have been
obtained for two different initial
enzyme concentrations for an
enzyme-catalyzed reaction.
[E] =0.015 g/1)
(g/l-min)
[S]
[E]=0.00875 g/)
(g/l-min)
1.14
0.87
0.70
0.59
0.50
0.44
0.39
0.35
20.0
10.0
6.7
3.0
40
3.3
29
2.5
0.67
0.51
0.41
0.34 -
0.29
5
a. Find Km.
b. Find Vm for [EO] = 0.015 g/1.​

Answer 1

Answer:

3.2. Enzyme Kinetics

A mathematical model of the kinetics of single-substrate-enzyme-catalyzed reactions was first developed by V. C. R. Henri in 1902 and by L. Michaelis and M. L. Menten in 1913. Kinetics of simple enzyme–catalyzed reactions are often referred to as Michaelis–Menten kinetics or saturation kinetics. The qualitative features of enzyme kinetics are similar to Langmuir–Hinshelwood kinetics (see Figure 3.3). These models are based on data from batch reactors with constant liquid volume in which the initial substrate, [S0], and enzyme, [E0], concentrations are known. More complicated enzyme–substrate interactions such as multisubstrate–multienzyme reactions can take place in biological systems.

Figure 3.3.

Figure 3.3. Effect of substrate concentration on the rate of an enzyme–catalyzed reaction.

An enzyme solution has a fixed number of active sites to which substrates can bind. At high substrate concentrations, all these sites may be occupied by substrates, or the enzyme is saturated. Saturation kinetics can be obtained from a simple reaction scheme that involves a reversible step for enzyme–substrate complex formation and a dissociation step of the enzyme–substrate complex: