title: Purification and characterization of a processing protease from rat liver mitochondria.
abstract: A processing protease has been purified from the matrix fraction of rat liver mitochondria. The purified protease contained two protein subunits of 55 kd (P-55) and 52 kd (P-52) as determined by SDS-PAGE. The processing protease was estimated to be 105 kd in gel filtration, indicating that the two protein subunits form a heterodimeric complex. At high ionic conditions, the two subunits dissociated. The purified processing protease cleaved several mitochondrial protein precursors destined to different mitochondrial compartments, including adrenodoxin, malate dehydrogenase, P-450(SCC) and P-450(11 beta), but the processing efficiencies were different each other. The endoprotease nature of the processing protease was confirmed with the purified enzyme using adrenodoxin precursor as the substrate; both the mature form and the extension peptide were detected after the processing. The processing activity of the protease was inhibited by metal chelators, and reactivated by Mn2+, indicating that the protease is a metalloprotease.
authors.affiliation: Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Japan.
authors.forename: W J
authors.initials: WJ
authors.lastname: Ou
authors.forename: A
authors.initials: A
authors.lastname: Ito
authors.forename: H
authors.initials: H
authors.lastname: Okazaki
authors.forename: T
authors.initials: T
authors.lastname: Omura
mesh_terms: D000325:Adrenodoxin / Q000378:metabolism; D000818:Animals; D002853:Chromatography, Liquid; D010450:Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D007163:Immunosorbent Techniques; D008345:Manganese; D008666:Metalloendopeptidases / Q000302:isolation & purification; D008930:Mitochondria, Liver / Q000201:enzymology*; D008970:Molecular Weight; D010446:Peptide Fragments; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D010446:Peptide Fragments; D011498:Protein Precursors; D000325:Adrenodoxin; D008345:Manganese; D010450:Endopeptidases; D008666:Metalloendopeptidases