Post-translational import of 3-ketoacyl-CoA thiolase into rat liver peroxisomes in vitro.
Cell-free translation products of hepatic free polysomal RNA from a clofibrate-treated rat were incubated at 26 degrees C for 0-60 min with a post-heavy mitochondrial supernatant fraction from normal rat liver. Exogenously added proteinase K-resistant precursor and mature forms of peroxisomal 3-ketoacyl-CoA thiolase were recovered in a particulate fraction and increased with time. Both forms of thiolase cosedimented with peroxisomes, when the proteinase K-treated import reaction mixture was centrifuged in a sucrose density gradient. The in vitro import and processing of thiolase precursors, types A and B, was likewise reproduced with highly purified peroxisomes. These results strongly suggest that the precursor form of 3-ketoacyl-CoA thiolase is translocated into peroxisomes, apparently without tight coupling with proteolytic processing to the mature protein.
Miura
S
S
Meiji Institute of Health Science, Kanagawa.
Miyazawa
S
S
Osumi
T
T
Hashimoto
T
T
Fujiki
Y
Y
D000102:Acetyl-CoA C-Acyltransferase / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002500:Centrifugation, Isopycnic; D005591:Chemical Fractionation; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008297:Male; D008830:Microbodies / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D051381:Rats; D017207:Rats, Sprague-Dawley
D000102:Acetyl-CoA C-Acyltransferase