C R Seances Acad Sci D. 1979 Nov 5;289(11):777-80.  

[Demonstration of "hydroxylase" and "epoxide hydrase" activities in preparations
of nucleoli isolated from rat liver]

[Article in French]

Lafarge-Frayssinet C, Alexandrov K, Dansette P, Guerry R, Frayssinet C.

Aryl hydrocarbon hydroxylase (AHH) activity and epoxyde hydrase (EH) activity
have been found in Rat liver nucleoli obtained from untreated (C) and
methylcholanthrene (MC) pretreated Rats. Electron microscopic observations of
nucleolar preparations did not reveal significant contamination either by intact
nuclei or by nuclear membranes. Very low but detectable activity of NADPH
cytochrome C reductase was found in the nucleoli. Nucleolar preparations
revealed little AHH activity (12-18 pmoles/min/mg). AHH was inducible by MC in
nuclei but not in nucleoli. The presence of EH in nucleoli was demonstrated with
phenanthrene 9,10-oxide (550-620 pmoles/min/mg) and benzopyrene 4,5-oxide
(92-116 pmoles/min/mg). These values were lower than those obtained using intact
nuclei. The addition of TCPO (10(-4) M) inhibited EH activity.

PMID: 118814 [PubMed - indexed for MEDLINE]