  Naively, one expects the information communicated by an enzyme downstream
within a signaling network, in which the enzyme is embedded, to grow
monotonically with the enzyme's rate of product formation. However, here we
observe that this does not necessarily hold true for allosterically regulated
enzymes, often observed in signaling networks. In particular, we find that the
mutual information between the catalytic sites of an allosterically regulated
enzyme and a receiver protein downstream in the signaling pathway depends on
the transition kinetics between the different allosterically regulated states
of the enzyme and their respective rates of product formation. Surprisingly,
our work implies that allosteric down-regulation of an enzyme's rate of product
formation may not only be used as a way to silence itself, as one would
normally expect. Rather, down-regulation may also be used to increase the
information communicated by this enzyme to a receiver protein downstream in a
signaling pathway.
