Biology Reference
In-Depth Information
Fig. 2. From the original
P
orig
to the high-level net
P
.
the
PPP
consists of the reactions
l
1,
m
1to
m
3,
r
1to
r
5, and
l
3to
l
8. From now on we use acronyms
for most metabolic substances; their full names are listed in the Abbreviations appendix.
It shall be noted that molecules like ADP, ATP, NAD
+
,P
i
etc. play a somewhat special role in
metabolic networks. They are called
ubiquitous
because they are found in sufficiently large amounts in
the cell. For ease of distinction, the remaining substances from Gluc to Lac shall be named
primary
.
When talking about reactions in the following, the involved ubiquitous molecules commonly are not
mentioned because the primary substances are those that characterize the reactions and hence are of
particular interest.
Whereas the
GP
generates primarily ATP with glucose as a fuel, the
PPP
generates NADPH, which
serves as electron donor for biosyntheses in cells. The interplay of the glycolytic and pentose phosphate
