Fig. 4: Selenium-catalyzed oxidation-based oscillators.

a A schematic representation of the CSTR experimental set-up and the downstream derivatization with Ellman’s reagent. The UV–Vis spectrometer detects the absorption of 4-nitro-3-carboxythiophenolate at 412 nm. b The reaction networks of selenium-catalyzed oxidation-based oscillators. The scheme describes oscillators with negative feedback consisting of the thiol-induced release of 7 from 3, 4, or 5. The oscillator with catalyst 2 has 2 in place of 7 and does not have a closed negative feedback loop. Colors represent key elements of the oscillatory network: blue—substrates, red—autocatalysts, and green – inhibitor. Bold plus and minus signs represent positive and negative feedback loops correspondingly.