Related Experiment Video
Updated: Jul 9, 2026

Quantifying Subcellular Ubiquitin-proteasome Activity in the Rodent Brain
Published on: May 21, 2019
[Ubiquitin causes selective increase in the sensitivity of rat brain mitochondrial monoamine oxidases to various
Abstract:
Incubation of rat brain mitochondria with ubiquitin and ATP followed by subsequent mitochondria sedimentation was accompanied by reduction of ubiquitin content in the supernatant. This decrease was more pronounced in the presence of ATP-regenerating system in the incubation medium (creatine phosphate/creatine phosphokinase). This ubiquitin incorporation into brain mitochondria observed only in the presence of ATP in the incubation medium increased sensitivity of monoamine oxidases (MAO) A and B to proteolytic inactivation by trypsin and papain, respectively. (Ubiquitin did not influence sensitivity of MAO B to trypsin and MAO A to papain). The data obtained suggest that ubiquitin incorporation into rat brain mitochondria increases susceptibility of MAOs to certain exogenous proteases, however, it remains unclear whether these changes stem from direct MAO-ubiquitin conjugation or reflect alterations in the membrane environment of these enzymes.
Related Concept Videos
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Drugs Affecting Neurotransmitter Synthesis

