TY - JOUR
T1 - Ubiquinone biosynthesis by mitochondria, sonicated mitochondria and mitoplasts of rat liver
AU - Kang, Dongchon
AU - Fujiwara, Toshiyuki
AU - Takeshige, Koichiro
PY - 1992/3
Y1 - 1992/3
N2 - Ubiquinone was biosynthesized when rat liver mitochondria were incubated with S-adenosyl-L-methionine, solanesyl diphosphate, and [U-14C]p-hydroxybenzoate. The intermediates of ubiquinone biosynthesis but not ubiquinone were accumulated in mitochondria incubated without S-adenosyl-L-methionine and the accumulated intermediates were converted to ubiquinone by the addition of the methyl group donor and an excess of cold p-hydroxybenzoate. No solaneylated compounds except nonaprenyl p-hydroxybenzoate were found in sonicated mitochondria, while the biosynthesis of ubiquinone was observed in the sonicated preparation of mitochondria in which the intermediates accumulated. The results indicate that the initial decarboxylation reaction is completely abolished and the subsequent reactions of hydroxylation and methylation are not completely inhibited by the sonication treatment and therefore the decarboxylation reaction is the next step after nonaprenylation of p-hydroxybenzoate. Mitoplasts could biosynthesize ubiquinone with activity comparable to that of intact mitochondria, suggesting that components of the outer membrane and the intermembranous space of mitochondria are not involved in ubiquinone biosynthesis.
AB - Ubiquinone was biosynthesized when rat liver mitochondria were incubated with S-adenosyl-L-methionine, solanesyl diphosphate, and [U-14C]p-hydroxybenzoate. The intermediates of ubiquinone biosynthesis but not ubiquinone were accumulated in mitochondria incubated without S-adenosyl-L-methionine and the accumulated intermediates were converted to ubiquinone by the addition of the methyl group donor and an excess of cold p-hydroxybenzoate. No solaneylated compounds except nonaprenyl p-hydroxybenzoate were found in sonicated mitochondria, while the biosynthesis of ubiquinone was observed in the sonicated preparation of mitochondria in which the intermediates accumulated. The results indicate that the initial decarboxylation reaction is completely abolished and the subsequent reactions of hydroxylation and methylation are not completely inhibited by the sonication treatment and therefore the decarboxylation reaction is the next step after nonaprenylation of p-hydroxybenzoate. Mitoplasts could biosynthesize ubiquinone with activity comparable to that of intact mitochondria, suggesting that components of the outer membrane and the intermembranous space of mitochondria are not involved in ubiquinone biosynthesis.
UR - http://www.scopus.com/inward/record.url?scp=0026606710&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026606710&partnerID=8YFLogxK
U2 - 10.1093/oxfordjournals.jbchem.a123764
DO - 10.1093/oxfordjournals.jbchem.a123764
M3 - Article
C2 - 1587800
AN - SCOPUS:0026606710
VL - 111
SP - 371
EP - 375
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 3
ER -