  Robustness of biochemical systems has become one of the central questions in
Systems Biology, although it is notoriously difficult to formally capture its
multifaceted nature. Maintenance of normal system function depends not only on
the stoichiometry of the underlying interrelated components, but also on a
multitude of kinetic parameters. For given parameter values, recent findings
have aimed at characterizing the property of the system components to exhibit
same concentrations in the resulting steady states, termed absolute
concentration robustness (ACR). However, the existing method for determining
system components exhibiting ACR is applicable only to one class of mass-action
networks for which this property can be confirmed, but not discarded. Here we
design a new method which relies on biochemical network decompositions into
subnetworks, called elementary flux modes, to identify ACR in a broader class
of mass-action networks by using only the given stoichiometry. This approach
reduces the problem of determining ACR to that of solving parameterized systems
of linear equations, rendering it amenable to networks of larger sizes. Our
unified framework will be helpful in analyzing this biologically important type
of robustness as well as detection of novel systemic properties independent of
the kinetic parameters for more complex biochemical networks.
