2-iodo-6-isopropyl-3-methyl-2',4,4'-trinitrodiphenyl ether

DNP-INT is a quinone analog that inhibits electron transport in plants by competitively inhibiting plastoquinol oxidation by binding at the Q_o site of cytochrome b₆f (K_d = 1.4 nM).¹ It inhibits electron flow from water to NADP or methylviologen by 50 and 100% when used at concentrations of 0.5 or 5 μM, respectively.^2,3

1. Barbagallo, R.P., Finazzi, G., and Forti, G. Effects of inhibitors on the activity of the cytochrome b6f complex: Evidence for the existence of two binding pockets in the lumenal site Biochemistry 38(39),12814-12821(1999).
2. Trebst, A., Wietoska, H., Draber, W., et al. The inhibition of photosynthetic electron flow in chloroplasts by the dinitrophenylether of bromo-or iodo-nitrothymol Z. Naturforsch. C J. Biosci. 33(11-12),919-927(1978).
3. Malkin, R. Interaction of stigmatellin and DNP-INT with the Rieske iron-sulfur center of the chloroplast cytochrome b6f complex. FEBS Lett. 208(2),317-320(1986).