198
Chapter 6
increase dramatically for increasing 1/s, since it is likely that
r
is determined experimentally with
a given absolute standard deviation irrespective of the value of
s
(which can always be
determined with a fixed relative standard error).
Once the correct type of inhibition has been found all parameters in the rate expression should be
determined by non-linear Least-Squares regression.
The
correlation
matrix
between the
parameters should be shown together with the estimate of the parameter vector and the standard
deviation of the parameters.
1/s
Figure 6.2 Lineweaver-Burk (double reciprocal plots) of the relation between the rate
r
and the substrate
concentration
s.
In all four plots the intersection P with the ordinate axis is k'1
in eq (6.1) for inhibitor
concentration 5, = 0 and the apparent value of
k'
according to (6.10), (6.14), and (6.16) respectively. |Q|
is the corresponding value of
Km
1
in (6.1) for s, = 0, and of the apparent value of
Km
1
for 5, greater than
zero. The slope of the lines is equal to
/ kapparenI.
A.
Competitive inhibition by S|,eq(6.10).
B.
Non-competitive inhibition by j,, eq (6.14).
C.
Un-competitive inhibition by s,, eq (6.16)
D.
Substrate inhibition by (6.16). Values of
k '
and of
Km
1
are obtained from the ordinate at
P
and
the abscissa at Q. Slope of the inclined asymptote is
KJk.
previous page 221 Bioreaction Engineering Principles, Second Edition  read online next page 223 Bioreaction Engineering Principles, Second Edition  read online Home Toggle text on/off