The cytochrome P-450 reaction mechanism--kinetic aspects.

The reviewed kinetic investigations at the experimentally accessible partial reactions of the reaction sequence clearly evidence that the P-450 system represents a complex reaction system, the main control points of which are shown in Scheme 3: As can be seen, control elements are the substrate, the cytochrome species (P-450/448), the reducing agent, the reductase, phospholipid and parts of the b5 system as well. Formula (see text): All of these steps can be rate limiting (rate interfering), depending on the distinct substrate and oxygen donor. The ternary complex evidently has a key position however in that is structural specificities determine rate and product distribution of the respective substrate conversion. But unfortunately the ternary complex decay (including the e2 transfer) is kinetically unresolved till now.