1H-NMR study of the interaction of aminopyrine with purified rat liver microsomal cytochrome P-450

AbstractLongitudinal relaxation (T1) measurements for all lines (N(CH3)2, N(CH3), (C(CH3), phenyl) in the aminopyrine 1H-NMR spectrum were used to study the interaction of aminopyrine with purified microsomal cytochrome P-450 from livers of phenobarbital-treated rats. The paramagnetic contribution to the observed t1−1 values was determined from its dependence on aminopyrine concentration. The Solomon-Bloembergen equation was used to calculate between Fe3+ and aminopyrine distances in the enzyme-substrate complex. For all protons these distances are about 8 Å