high molecular inhibitor of CYP1A1

CWFisher cwfisher at aol.com
Tue Aug 29 12:31:35 EST 1995

How about using an affinity column of CYP1A1 or CYP1A2?  CYP 1A2 can be
expressed in high levels in E. coli (see Fisher, C.W. et al (1992) FASEB
J. 760, 759-764).  We have made fusions of reductase and cytochrome P450
which can be bound to AMP-Sepharose.  Any bound protein could be eluted as
a complex with the fusion protein using 5'2' AMP.

An important question is does the inhibitor actually inhibit the reaction
or does it reduce the 7 OH resorufin?  7 OH resorufin undergoes redox
cycling which can interfere with the assay determination (see articles by
Andrew Parkinson), perhaps you are seeing some type of reductase acting on
the product of the reaction.  If the inhibitor actually inhibits other
CYP1A1 reactions then the question is whether the inhibition is due to
interaction with the reductase or with the CYP 1A1?  You should also assay
other types of P450 mediated reactions to see if the inhibition is
specific for CYP 1A1.

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