2,5-Diphenyloxazole as a probe for microsomal mono-oxygenation in human and rat liver

Publisher Website
Google Scholar
Abstract
1. 2,5-Diphenyloxazole (PPO) is metabolized to one major fluorescent product by human liver and rat liver microsomes. 2. PPO metabolism by human-liver microsomes involves more than one cytochrome P-450 isozyme, termed low-affinity and high-affinity components. At a substrate concentration of 0±1 μM, 95% of activity is due to the high-affinity component whereas at 100 μM 69% of activity is due to the low-affinity component. 3. Inhibition studies with metyrapone and α-naphthoflavone at 0±1 μM and 100 μM suggest that the high-affinity component may reflect a 3-methylcholanthrene-inducible form of cytochrome. Therefore studies at low substrate concentrations may be a useful tool for cytochrome P-450 studies in man. 4. Rat liver microsomes show linear kinetics indicating the involvement of one major form of cytochrome P-450.

This publication has 14 references indexed in Scilit: