Fig. 6: Kinetic studies of thiouronium salt-based oscillators. | Nature Communications

Fig. 6: Kinetic studies of thiouronium salt-based oscillators.

From: Autocatalytic and oscillatory reaction networks that form guanidines and products of their cyclization

Fig. 6

Experimental conditions shared by all experiments: H2O, 1 M PB pH 8, at 25 °C; [8] = 56 mM; [17] = 92 mM; [Acrylamide] = 321 mM; other parameters are indicated for specific experiments. a Experimental data showing sustained oscillations in the system that used maleimide to delay autocatalysis. [Maleimide] = 8 mM; f/V = 1.61 × 10−4 s−1. b Experimental data showing sustained oscillations in the system that used K3[Fe(CN)6] to delay autocatalysis. [K3[Fe(CN)6]] = 5.53 mM; f/V = 1.34 × 10−4 s−1. c Experimental data showing the distribution of thiols during oscillations. [Maleimide] = 6.2 mM; f/V = 1.34 × 10−4 s−1. d Phase plot reconstructed from 33 oscillatory experiments (Supplementary Section 6). Black circles denote oscillatory points; white circles denote points with damped oscillations or no oscillations; back and white circles denote special cases. The point at [Maleimide] = 6.2 mM; f/V = 1.34 × 10−4 s−1 is a borderline case that demonstrates sustained oscillations in about 50% of the cases that depend on fluctuations in the experimental conditions. The points at [Maleimide] = 6.2 mM; f/V = 2.42 × 10−4 and 2.96 × 10−4 s−1 represent locally stable steady states. The red and blue colors denote the result of the linear stability analysis of the three-variable model with the following parameters: [8] = 56 mM; k1 = 0.507 s−1 M−1, k2 = 300 s−1 M−1, k3 = 0.0099 s−1, k4 = 3.7 × 10−5 s−1 (Supplementary Section 7)60. e The experimental observation of the locally stable steady state. [Maleimide] = 4 mM; f/V = 2.96 × 10−4 s−1. f Observation of the locally stable steady state in the three-variable model. Modeling parameters: [8] = 56 mM; [Maleimide] = 4 mM; f/V = 2.96 × 10−4 s−1; k1 = 0.507 s−1 M−1, k2 = 300 s−1 M−1, k3 = 0.0099 s−1, k4 = 3.7 × 10−5 s−1. Initial conditions that result in the steady state: [8]0 = 20 mM; [Maleimide]0 = 5 × 10−3 mM; [RSH] = 2 mM. Initial conditions that result in the sustained oscillation: [8]0 = 56 mM; [Maleimide]0 = 4 mM; [RSH] = 0 mM.

Back to article page