32
Chapter 2
T a b le 2.5 C om position and A TP and N A D PH requirem ents o f
E. coli
cell
1
mass.
Species
C o n ten t
A T P
N A D P H
(e
(ft
DW Y1)
(Mmoles (e D W Y 'l
(Mmoles (e DW VT
Protein
0.55
29,257
(21,970)
11,523
(0)
RN A
0.20
6,796
(2,146)
427
(0)
rRN A
0.16
tR N A
0.03
m R N A
0.01
D N A
0.03
1,240
(450)
200
(0)
Lipid
0.09
2,836
(387)
5,270
(0)
L ipopolysaccharide
0.03
470
(125)
564
(0)
Peptidoglycan
0.03
386
(193)
193
(0)
G lycogen
0.03
154
(154)
0
(0)
B uilding blocks
0.04
Total
1.00
41.139
(25.4251
18.177
J O T _____
* The data are for balanced growth at 37 0C on a glucose minimal medium and a specific growth rate o f 1.04 h 1. The
content o f species is given as mass fraction o f total cell weight. The data in parenthesis for ATP and NADPH
requirements are for growth on a rich medium containing all the necessary building blocks (amino acids, nucleotides,
fatty acids, etc.) The data are taken from Ingraham
et al.
(1983).
T a b le 2.6 M easurem ents o f the concentrations o f A M P, A D P, and A T P in
Lactococcus
lacks at different
specific grow th rates obtained in a chem ostat at steady state and calculation o f the total adenylate pool and
the energy charge.“
Specific g ro w th ra te
S u b stra te
[A M P]
[A D P]
[A TP]
T o ta l
E n erg y
f l i 1!
a d e n v late
d o o I
c h a rg e
0.03
G lucose
12
17
25
54
0.62
0 .4 8
17
23
52
92
0.69
0.69
15
27
50
92
0.69
0.15
M altose
5
8
20
33
0.73
0 .3 2
12
23
41
76
0.69
0.58
17
26
44
87
0.66
* All concentrations are in Mmole per gram dry weight. The data are taken from Sjôberg and Hahn-Hagerdal ( 1989).
The results of Table 2.6 are only true for balanced growth where the anabolic processes
immediately utilize the ATP generated by the catabolic processes. Dramatic, and very fast changes
in the energetic state of the cell will accompany abrupt changes in the environment - for example
when a pulse of glucose is added to a steady state cultivation growing a low glucose concentrations.
Reuss and coworkers (Theobald
et al.,
1993; Theobald
et a l
, 1997; Vaseghi
et a l,
1999) have
made some - both from a scientific and from an experimental methodology point of view - very
interesting studies of the rapid changes of metabolite levels that accompany an abrupt change in the
environment. The experiments were made with an aerobic yeast culture grown on glucose, and
results have been obtained in several time windows (depending on the experimental technique)
ranging from 0 to 100 seconds or from 0 to 1 second. Figure 2.7 shows results in the 0 to 100
seconds time window for the changes in adenylate concentrations.
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