A submitochondrial particle (SMP) is an artificial

vesicle Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry) In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form nat ...

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 Osmotic shock or osmotic stress is physiologic dysfunction caused by a sudden change in the solute concentration around a cell, which causes a rapid change in the movement of water across its cell membrane. Under hypertonic conditions - conditions ...

. SMPs can be used to study the electron transport chain 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'' (franchis ...

-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 agent A chaotropic agent is a molecule in water solution that can disrupt the hydrogen bonding network between water molecules (i.e. exerts chaotropic activity). This has an effect on the stability of the native state of other molecules in the solution, ...

s can destabilize F₁ particles and cause them to dissociate from the membrane, thereby uncoupling the final step of oxidative phosphorylation from the rest of the electron transport chain.

References

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