Fig. 4
In contrast to Endoxifen, trans-4-OHT loses its potency over time independently from isomerization. (A) Switching efficiency was quantified comparing fresh and 12 weeks old trans-4-OHT and Endoxifen (scale bar 500 µm). (B) mCherry intensity in embryos treated with 12 weeks old trans-4-OHT is approximately half compared to intensities measured in embryos induced with fresh trans-4-OHT (two-tailed, unpaired t-test, p<0.0001). The potency of Endoxifen does not change significantly throughout the same time period (two-tailed, unpaired t-test, p = 4598). (C) The 1H NMR spectrum of trans-4-OHT freshly dissolved in DMSO-d6 reveals the presence of ≥98% of the trans isomer. (D) After 5 months storage in DMSO-d6, no appreciable change in isomer composition can be detected by 1H NMR.