Tissue distribution of a major mevalonate pyrophosphate decarboxylase in rats.
The 45- and 35-kDa subunits of mevalonate pyrophosphate decarboxylase (MPD) have been purified from rat liver. In this study, we examined the relationship between 45- and 35-kDa MPD and the tissue distribution of a major MPD in rat liver. When the crude extract of rat liver fed on normal chow was subjected to immunoblot analysis using anti-rat 45-kDa MPD antibody, only the 45-kDa band was detected. In a pulse-chase experiment using anti-rat 45-kDa MPD antibody, there was no precursor-product relationship between the 45- and the 35-kDa MPD. In immunoprecipitation, more than 85% of MPD activity in the rat liver was depleted from the crude extract with an excess of the above antibody. When 45-kDa MPD contents in tissues were analyzed by immunoblotting, a single protein band with an apparent molecular weight of 45 kDa was detected in all tissues. The specific protein content of 45-kDa MPD in liver was markedly higher than in other tissues. The activity/amount ratio varied among brain, liver, and testis, being significantly highest in the liver. From these data, it is suggested that 45-kDa MPD serves as a major enzyme involved in cholesterol biosynthesis in rat liver and that a tissue-specific regulator or isozyme of 45-kDa MPD is present in rat liver.
Michihara
A
A
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan. mitihara@fupharm.fukuyama-u.ac.jp
Akasaki
K
K
Yamori
Y
Y
Tsuji
H
H
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D002262:Carboxy-Lyases / Q000378:metabolism*; D004789:Enzyme Activation; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D008970:Molecular Weight; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar; D013737:Testis / Q000187:drug effects / Q000201:enzymology
D007527:Isoenzymes; D002262:Carboxy-Lyases; C022503:pyrophosphomevalonate decarboxylase