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Figure 4
Myoglobin and azide time-resolved absorbance measurements in the cone opening device. Images of the cone opening Kenics and observation region during the absorbance experiment. (a) Cone opening Kenics in the observation tube. (b) Dark-subtracted image of the observation region for myoglobin mixing with azide. Striations visible in the image result from the cross-shaped homogenizer and occur in the reference image as well. (c) Image showing transmission. (d) Absorbance versus time for each of the three azide concentrations, with fits overlaid. The legend applies to all panels. (e) Fraction of unbound myoglobin versus time. (f) Log plot of fraction unbound versus time. The slight discontinuity in the data at ∼45 ms can be attributed to a mismatch in the two modules of the camera detector. (g) Table showing the dead time (tdead), time constant (τ) and reaction constant (k) for each azide concentration. Notably, the k values are a good match to the literature (2.8 ± 0.3 × 103 M−1s−1; Nami et al., 2016BB34). These values were extracted from fitting the absorbance versus time data.

IUCrJ
Volume 10| Part 3| May 2023| Pages 363-375
ISSN: 2052-2525
https://doi.org/10.1107/S2052252523003482