Amine nitrosation by sodium nitroprusside

Nitrosamine formation from the reaction of nitroprusside with morpholine was found to be a light-dependent reaction. Maximum nitrosation occurred when the reactants were exposed to UV light (lambda = 275-300 nm). However, considerable nitrosation also occurred with light in the visible spectrum up to 500 nm. No significant nitrosamine formation was observed when the reactants were kept in the dark. Data concerning the effects of other physical and chemical factors such as pH, temperature and reactant concentration on the reaction between morpholine and sodium nitroprusside are also presented.

Kinetic study of the enzyme NADPH cytochrome-C (P-450) reductase: non-Michaelian behaviour

1. Contrary to what has been accepted until now, the enzyme exhibits non-Michaelian kinetics both against NADPH and against cytochrome-c as substrates; deviations were detected that have led to the proposition of a rate equation of minimum degree 2:2. 2. A general mechanism is proposed that includes, apart from the binding of the enzyme to NADPH, the formation of an enzyme-cytochrome-c complex, both routes leading to the formation of a ternary-complex NADPH-enzyme-acceptor. 3. From the latter, a series of intermediate steps finally leads to the release of the enzyme in conditions to start a new catalytic cycle. 4. Application of the King-Altman method to this mechanism yields a kinetic equation of degree 2:2 with respect to the cytochrome-c and NADPH, in accordance with our experimental results.