Studies on the substrate-binding sites of liver microsomal cytochrome P-448.

نویسندگان

  • C E Phillipson
  • C Ioannides
  • M Delaforge
  • D V Parke
چکیده

The interaction of substrates of the microsomal mixed-function oxidases with cytochromes P-450 and P-448 was investigated by using liver microsomes from rats pretreated with phenobarbital or 3-methylcholanthrene, and with purified forms of the cytochromes isolated from rabbit liver. The two forms of the cytochrome have different substrate specificities; cytochrome P-450 has one type 1 substrate-binding site that can accommodate a large variety of substrates, but in contrast cytochrome P-448 may possess two type 1 substrate-binding sites, one of which is different to that of cytochrome P-450 in that it shows a specificity for substrates such as safrole and 9-hydroxy-ellipticine. These findings explain why the two forms of the cytochrome have different substrate specificities and play contrasting roles in the activation and deactivation of xenobiotics.

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عنوان ژورنال:
  • The Biochemical journal

دوره 207 1  شماره 

صفحات  -

تاریخ انتشار 1982