Re-investigation of the presence of UDP-glucuronosyltransferase in rat liver mitochondria.
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.
D000818:Animals; D004721:Endoplasmic Reticulum / Q000201:enzymology; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D011506:Proteins; D014453:Glucuronosyltransferase; D005952:Glucose-6-Phosphatase