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. Author manuscript; available in PMC: 2012 Dec 4.
Published in final edited form as: Biochim Biophys Acta. 2010 Jul 21;1804(11):2136–2145. doi: 10.1016/j.bbapap.2010.07.013

Fig. 3.

Fig. 3

Denaturation of Magnaporthe grisea KatG1 and Synechocystis KatG by urea as monitored by fluorescence spectroscopy. (A) Fluorescence emission spectra of Magnaporthe grisea KatG (0.5 μM) in 5 mM phosphate buffer, pH 7.0, upon 18 h (25 °C) incubation with various concentrations of urea [0 M (gray line), 2.25, 2.5, 3.5, 4, 5.25, 7.25 and 7.8 M]. (B) Fluorescence emission spectra of Synechocystis KatG (0.5 μM) in 5 mM phosphate buffer, pH 7.0, upon 18 h (25 °C) incubation with various concentrations of urea [0 M (gray line), 0.25, 0.5, 1, 1.75, 3, 5, 6.5, and 7.5 M]. (C, D) Plot of change in Trp emission maximum versus urea concentration. Conditions as in (A, B). The inset depicts the corresponding stability curve (ΔG° versus urea concentration) and fit for the second transition. Gray spectra and circles indicate first transition (≤2.25 M urea), black spectra and circles represent second transition. Excitation: 295 nm, emission range: 300–450 nm.