A submitochondrial particle (SMP) is an artificial

vesicle Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle ; In human embryology * Vesicle (embryology), bulge-like features ...

made from the

inner mitochondrial membrane The inner mitochondrial membrane (IMM) is the mitochondrial membrane which separates the mitochondrial matrix from the intermembrane space. Structure The structure of the inner mitochondrial membrane is extensively folded and compartmentalized. ...

. They can be formed by subjecting isolated mitochondria to

sonication A sonicator at the Weizmann Institute of Science during sonicationSonication is the act of applying sound energy to agitate particles in a sample, for various purposes such as the extraction of multiple compounds from plants, microalgae and seawe ...

, freezing and thawing, high pressure, or osmotic shock. SMPs can be used to study the

electron transport chain An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couple ...

in a cell-free context. The process of SMP formation forces the inner mitochondrial membrane inside out, meaning that the

matrix Matrix most commonly refers to: * ''The Matrix'' (franchise), an American media franchise ** '' The Matrix'', a 1999 science-fiction action film ** "The Matrix", a fictional setting, a virtual reality environment, within ''The Matrix'' (franchi ...

-facing leaflet becomes the outer surface of the SMP, and the intermembrane space-facing leaflet faces the lumen of the SMP. As a consequence, the F₁ particles which normally face the matrix are exposed. Chaotropic agents can destabilize F₁ particles and cause them to dissociate from the membrane, thereby uncoupling the final step of

oxidative phosphorylation Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine t ...

from the rest of the electron transport chain.

References

Cellular respiration Membrane biology Mitochondria {{Molecular-cell-biology-stub