Although not all of the quoted systems fulfill the exact definition of
being allosteric, at least their function corresponds to an allosteric
behavior, which is defined as: A term to describe proteins that have two
or more receptor sites, one of which (the active site) binds the principal
substrate, whereas the other(s) bind(s) effector molecules that can
influence its biological activity. This definition can be used for artificial
systems as well.
reaction mixture more complex. Only a fraction of the flavin may
be available for copper photoreduction.
In summary, we have described a simple photo-regulated
system, which is able to convert a light signal input into a
correlated chemical output with amplified response. Although its
fidelity in terms of sensitivity and amplification is still far from
biological models or classical photography, it illustrates how
coupled chemical processes may allow the transformation and
amplification of information at the molecular level.
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We acknowledge financial support from the DFG SPP 1118.
S.C.R. thanks the Elitenetzwerk Bayern for a graduate fellowship.
Notes and references
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{ All reactions were performed under an inert atmosphere using standard
Schlenk techniques. Acetonitrile (HPLC-grade, Baker) was freshly distilled
over sodium hydride and P4O10. Fluorescence measurements were done in
acetonitrile (UV-grade, Baker) at 25 uC and recorded on a Varian ‘Cary
Eclipse’ fluorescence spectrophotometer.
General procedure: Azide 2 (127.8 mg, 0.4 mmol) was dissolved in a
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aliquots of 20 ml were taken every minute. The samples were added to a
solution of 20 ml of 30% aqueous H2O2 in 2000 ml acetonitrile to stop the
reaction. Samples of 60 ml of this solution were diluted with 3000 ml
acetonitrile and emission spectra were recorded. See electronic supplemen-
tary information (ESI) for further details.{
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11 Experimentally determined.
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4696 | Chem. Commun., 2006, 4694–4696
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