Model of Esomeprazole complexed to a Cytochrome P450. Adatpted from x-ray crystal structure 4O4P from the RSCB Protein Data Bank. Original work from Butler, C.F., Peet, C., McLean, K.J., Baynham, M.T., Blankley, R.T., Fisher, K., Rigby, S.E., Leys, D., Voice, M.W., Munro, A.W., "Human P450-like oxidation of diverse proton pump inhibitor drugs by 'gatekeeper' mutants of flavocytochrome P450 BM3." (**2014**) Biochem.J. *460*, pp. 247-259.