Biomedical Engineering Reference
In-Depth Information
Saturation region
(a)
[S]
0
[S]
[P]
[ES]
[E]
0
0
[E]
log (Time)
(b)
[S]
0
[P]
[S]
[ES]
[E]
0
[E]
0
0
Time
FIGURE 8.9
Time course of the formation of an enzyme/substrate complex and initiation of the pseudosteady
state and the completion in a batch reactor, as derived from the two kinetic steps on a typical enzyme, Eqn
(8.2)
with
k
2
¼
10 [E]
0
. (a) Concentration verse log (time). The pseudosteady state, i.e. when
constant concentrations of [ES] and [E] are reached and beyond, is shown clearly in this plot. (b) Concentration
verse time plot. The establishment of the pseudosteady state is accomplished in a very short time period, and it
nearly shows a step change at time 0 in this linear plot.
0.01 k
1
, k
1
¼
0.8 k
1
, and [S]
0
¼
8.2.3. Specific Activity
Enzyme concentrations are often given in terms of “units” rather than in mole or mass
concentration. We rarely know the exact mass of the enzyme in a sample, since it is generally
prepared via isolation of the enzyme from microorganisms or animal or plant tissues and
often contains a great deal of non-catalytic protein, the amount of which may vary from
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