Exoenzyme
Encyclopedia
An exoenzyme, or extracellular enzyme, is an enzyme
that is secreted by a cell
and that works outside of that cell
. It is usually used for breaking up large molecules that would not be able to enter the cell otherwise.
This term is also often used to refer to the hydrolytic digestive enzymes secreted by fungi.
Examples of extracellular enzymes:
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that is secreted by a cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
and that works outside of that cell
Extracellular
In cell biology, molecular biology and related fields, the word extracellular means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid...
. It is usually used for breaking up large molecules that would not be able to enter the cell otherwise.
This term is also often used to refer to the hydrolytic digestive enzymes secreted by fungi.
Examples of extracellular enzymes:
- AmylaseAmylaseAmylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns...
- ACEAngiotensin-converting enzymeAngiotensin I-converting enzyme , an exopeptidase, is a circulating enzyme that participates in the body's renin-angiotensin system , which mediates extracellular volume , and arterial vasoconstriction...
: generation of angiotensin-II - Lipoprotein lipase: release of lipids from circulating lipoproteins
- Digestive enzymes: breakdown of ingested nutrients
- Some clotting factors: e.g. thrombinThrombinThrombin is a "trypsin-like" serine protease protein that in humans is encoded by the F2 gene. Prothrombin is proteolytically cleaved to form thrombin in the first step of the coagulation cascade, which ultimately results in the stemming of blood loss...