Different amounts of cytochrome P-450 dependent monooxygenases in tulip bulbs, pea seedlings and maize endosperm cells

We determined the content of cytochromes P-450 and b5, NADPH cytochrome c reductase and some monooxygenases such as benzo[a]pyrene hydroxylase, aniline hydroxylase, aminopyrine demethylase and ethoxycoumarin deethylase in the microsomal fraction from dormant tissues of tulip bulbs, pea seedlings and maize endosperm cells. Cytochromes P-450 and b5 are present in all three microsomal preparations with maximum concentrations in tulip bulbs. Benzo[a]pyrene hydroxylase and aminopyrine demethylase are present in all three microsome preparations with maximum activity in maize endosperm cells and tulip bulbs, respectively. Ethoxycoumarin deethylase is also present in all three plants with no significant variations. NADPH cytochrome c reductase activity was detected only in tulip bulbs and in pea seedlings. Aniline hydroxylase was undetected in all preparations studied.