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. 2005 Jul 5;389(Pt 2):549–558. doi: 10.1042/BJ20042118

Figure 1. Reaction kinetics of ODNB, DTNB and 2-DTP with tubulin-SH at 25 °C.

Figure 1

Tubulin (1.0 μM=20.0 μM SH) in Mes a.b. (pH 6.5) was treated with 0.5 mM ODNB (curve 1), DTNB (curve 2), 2-DTP (curve 3) or 0.5 mM reagents in the presence of 4 M urea (curve 4). With DTNB and 2-DTP, reactions were 97±1.5% (19.4±0.3 SH) complete, and with ODNB, the reaction was 90±1.5% (18.0±0.3 SH) complete; with 4 M urea, the reaction was 98±1.0% complete within the mixing time. Curve 5, microtubules were assembled in taxol buffer (20 μM taxol and 10% DMSO in Mes a.b.) at 37 °C for 30 min, pelleted, washed twice, resuspended in taxol buffer and then treated with DTNB for different time periods at a DTNB/SH molar ratio of 50:1. Samples were removed at different time points, pelleted and supernatant solutions were assayed at 412 nm.