Kinetics of 125I-ubiquitin conjugation with and liberation from rabbit reticulocyte stroma.
The breakdown of mitochondria-containing stroma of rabbit reticulocytes is an ATP- and ubiquitin-dependent process and there is no evidence for an ATP-dependent but ubiquitin-independent proteolysis in these cells. The ubiquitin conjugate formation with heat-denatured stroma proteins is about one-fifth of that with native stroma. In reticulocytes there exist two mechanisms of ubiquitin liberation from its conjugates with stroma proteins: an ATP-dependent and hemin-resistant release of ubiquitin, which is assumed to be the first step in the degradation of ubiquitin conjugates by the protease system, and a release of ubiquitin catalyzed by an isopeptidase activity.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D019759:Carbon-Nitrogen Lyases; D004492:Edetic Acid / Q000494:pharmacology; D006427:Hemin / Q000494:pharmacology; D006609:High Mobility Group Proteins / Q000097:blood*; D006358:Hot Temperature; D007700:Kinetics; D008190:Lyases / Q000097:blood; D008274:Magnesium / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000097:blood; D011489:Protein Denaturation; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D013997:Time Factors; D014452:Ubiquitins / Q000097:blood*
D006609:High Mobility Group Proteins; D014452:Ubiquitins; D006427:Hemin; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D010447:Peptide Hydrolases; D008190:Lyases; D019759:Carbon-Nitrogen Lyases; C034300:isopeptidase; D008274:Magnesium