Phosphoprotein


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Phosphoprotein

 

any of the conjugated proteins containing a phosphoryl group bonded to the amino acid residues of the polypeptide chain. Usually, the phosphoryl group (—PO32–) is bonded to the phosphoprotein molecule through residues of the amino acids serine and threonine; in the mitochondria in animal tissues, phosphoproteins have been found in which the phosphoryl group is bonded to the protein through the imidazole ring of histidine. The transfer of the phosphoryl residue to the protein is catalyzed by the enzyme protein kinase, one of the phosphotransferases; here, adenosine triphosphate is the phosphate donor. Alkalies bring about a nonenzymatic separation of the phosphoryl group; in the presence of acids, however, phosphoproteins are relatively stable.

Phosphoproteins include casein, a basic protein in milk, and ovalbumin and vitellin, which are present in eggs. Also included are phosphorylated modifications of histones, RNA polymerases, certain phosphotransferases, and phosphatases. Phosphoproteins are very common in living organisms, where they figure in metabolism, in the regulation of the activity of cell nuclei, in ion transport, and in oxidation processes in mitochondria.

REFERENCE

Lisovskaia, N. P., and N. B. Livanova. Fosfoproteiny. Moscow, 1960.

V. V. ZUEVSKII

References in periodicals archive ?
Lung secreted phosphoprotein 1 (SPP1) expression in response to silica treatment in male and female C57BL/6J mice.
Slides were incubated for 1 h at room temperature in phosphoprotein stain (Invitrogen #MP33300; Thermo Fisher Scientific) while protected from light, destained for 3 x 30 min with a destaining solution specific to the stain (Invitrogen, #P33310; Thermo Fisher Scientific), and washed again for 2 x 10 min in ultrapure water.
12] receptor, measured in a vasodilator-stimulated phosphoprotein (VASP) flow-cy-tometry assay, at the end of 2 weeks of treatment with either cilostazol or placebo.
A good example is casein-A phosphoprotein, a material extracted from milk and then processed in various ways for use in plastic, dietary supplements, glue, cotton candy, protective coatings and paints, according to Ecology Coatings.
Several RRT-PCR assays were also developed for detection of human metapneumovirus (hMPV) targeting fusion (F), nucleoprotein (N), phosphoprotein (P), and polymerase (L) genes (MAERTZDORF et al.
Phosphorylation of focal adhesion vasodilator-stimulated phosphoprotein at Seri57 in intact human platelets correlates with fibrinogen receptor inhibition.
Herz C, Aumailley M, Schulte C et al: Kindlin-1 is a phosphoprotein involved in regulation of polarity, proliferation, and motility of epidermal keratinocytes.
The protein P53 is a nuclear phosphoprotein that regulates the transcription of DNA, cellular proliferation and cellular apoptosis.
Phosducin, a light-regulated phosphoprotein, binds to subunits of transducin, a transducer G protein (Lee et al.
BCL-6 gene product, a 92- to 98-kD nuclear phosphoprotein, is highly expressed in germinal center B cells and their neoplastic counterparts.
Disappearance and reappearance of the nuclear envelope (NE) during cell cycle is controlled by intermediate filament phosphoprotein called lamin.