Re-investigation of the presence of UDP-glucuronosyltransferase in rat liver mitochondria
Zaleski, J.; Gessner, T.
Research Communications in Chemical Pathology and Pharmacology 37(2): 279-292
1982
ISSN/ISBN: 0034-5164 PMID: 6291111 Document Number: 191178
Specific activities of UDP-glucuronosyltransferase and glucose-6-phosphatase, a marker enzyme of endoplasmic reticulum, were measured in mitochondria and microsomes. In mitochondria the specific activity of UDP-glucuronosyltransferase represented only 7-11% of that found in microsomes, when measured in the presence of various aglycone substrates, including 4-nitrophenol, 4-methylumbelliferone, 1-naphthol, phenolphthalein, testosterone and 17 beta-estradiol. Similarly, the specific activity of glucose-6-phosphatase in mitochondrial preparations was about 80% of that found in microsomes. In conclusion, it seems that in rat liver the UDP-glucuronosyltransferase activity associated with mitochondrial fractions reflects the presence of membrane fragments derived from endoplasmic reticulum, rather than mitochondrial location of this enzyme.