Compartmentalization (biology)


 * ''For other uses, see Compartmentalization

In biology, compartmentalization is the method intracellular organelles use to isolate different conditions from other organelles. For example, mitochondria and lysosomes are bounded with membranes. Within the membrane-bound compartments, different intracellular pH, different enzyme systems, and other differences are isolated. This enables the cell to carry out different metabolic activities at the same time. With mitochondria, the cytosol has an oxidising atmosphere which converts NADH to NAD+. With these cases, the compartmentation is physical. For protein synthesis, all the organs used for it are relatively near one another, the nucleolus makes the ribosomes which synthesize the proteins, the Rough ER is near the nucleus as well. The golgi body is also near the Rough ER for packaging and redistributing.

There exists also, chemical compartmentation, as with the case of Pyruvate dehydrogenase complex. This is the enzyme which catalyses Pyruvate decarboxylation, the reaction of Pyruvate with Coenzyme A and the major entry point into the TCA cycle:
 * Pyruvate + Coenzyme A + NAD+ ⇒ acetyl-CoA + NADH + H+ + CO2

Pyruvate dehydrogenase has three chemical compartments; E1 ( pyruvate decarboxylase), E2 (dihydrolipoyl transacetylase) and E3 ( dihydrolipoyl dehydrogenase). Each one of the compartments has its own specific function.