Sorption of enzymes on the cell membrane and subcellular structures: mechanisms, biological role (Review)

Abstract

Many cellular enzymes reversibly bind to the cell membrane and cytoskeleton components, sorption/
desorption is an important mechanism for regulating the activity of such enzymes and enzyme systems, as well as one of the ways of signal transmission in the cell. The study of the mechanisms of enzyme adsorption
allows not only to regulate the level of their activity, but also makes it possible to control intracellular
signaling. As examples, some enzymes of glycolysis, antioxidant system are considered; as an example of
enzymes involved in signal transmission – NO-synthase, a number of protein kinases.
Changes in the localization of enzymes in the cell occurs both due to changes in the parameters of
the intracellular medium, and as a result of covalent protein modification (phosphorylation, acylation, etc.).
In some cases, sorption on the membrane causes an increase in the local concentration of the substrate, which
leads to an increase in the activity of the enzyme; apparently, this may be associated with the localization on
the membrane of such antioxidant enzymes as SOD and catalase.
The mechanism of change in enzyme activity during their sorption on the membrane can be due to
changes in the microenvironment, conformational mobility of the protein, screening of the active center; the
allosteric mechanism of regulation of enzyme activity can change. Since all these processes must be reversible,
the sorption of enzymes in these cases is carried out due to weak force – hydrogen bonds, electrostatic or
hydrophobic interactions.
Many cytosolic proteins perform their functions in the membrane-associated state. Their association
with the surface of the membrane occurs with the help of structural protein modules (domains) that have specificity
to certain lipids. Cytosolic effector proteins have structural domains that can bind to the phosphoinositides
of the membrane surface. In the association with membranes the proteins-effectors are mostly in a
complex with phosphoinositide-specific kinases and phosphatases, and small GTPases what is necessary for
address аssociation protein effectors with membranes of organelles.