### Speaker

Dr
Petter Holme
(Coputational Biology)

### Description

This year is the 10th anniversary of the discovery that
metabolic networks are scale-free. I will make a brief
review of this decade of research relating network topology
and function in metabolic reaction systems with a focus on
our contributions. I discuss the hypothesis that network
clusters correspond to functional modules. Metabolic
network, however represented, are not as distinctly modular
as the cartoon picture of intricately wired subsystems with
few I/O-terminals. Does this reflect a trade-off between
functionality and robustness, or is it an inevitable
consequence of non-enzymatic reaction kinetics, or something
else? I also discuss optimal levels of representations—if
one uses a multiplex, directed, and perhaps bipartite,
representation one can encode more information, but standard
methods are harder to apply. If one goes for a simple-graph
representation with vertices connected by undirected edges,
then how can one encode as much functional information as
possible? I will also mention how one can use other types of
reaction systems, like reactions in planetary atmospheres,
as null-models of metabolic networks. Finally I look forward
and discuss open questions within reach with current and
future data sets.