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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.


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


References in periodicals archive ?
The Rb gene is a tumor suppressor gene encoding a 110-kd nuclear phosphoprotein.
Distribution of phosphoprotein p19 in rat brain during ontogeny: Stage-specific expression in neurons and glia.
Steroid regulation of cell specific secreted phosphoprotein 1 (osteopontin) expression in the pregnant porcine uterus.
Secreted phosphoprotein 1 (SPP1, osteopontin) binds to integrin alpha v beta 6 on porcine trophectoderm cells and integrin alpha v beta 3 on uterine luminal epithelial cells, and promotes trophectoderm cell adhesion and migration.
today launched a service program to provide phosphoprotein analysis of pre-clinical samples for pharmaceutical and biotechnology companies.
Structural disorder within the Sendai virus nucleoprotein and phosphoprotein
Amplified products ([approximately equal to] 238 bp from the nucleoprotein [N] gene and [approximately equal to] 425 bp from the phosphoprotein [P] gene) were sequenced and compared with sequences of DMV and other morbilliviruses by using BLASTN (http://blast.
a privately held biotechnology company, has entered into an agreement with GlaxoSmithKline (China) R&D Company Limited (GSK) to collaborate on Signum's phosphatase screening technology and Phosphoprotein Phosphatase 2A (PP2A).
Assays designed to detect changes in expression of RNA, proteins (both secreted and intracellular), and phosphoprotein targets are now commonly used to analyze blood samples.
Researchers use our products to discover subtle details about phosphoprotein signaling in a wide variety of biological systems.
Every time these researchers synthesize a phosphopeptide, they will use this AB SCIEX system exclusively to validate it, making it the research team's one-stop validation system for phosphoprotein synthesis.
ORF1 encodes a nonstructural protein of 1,596; ORF2 encodes a capsid protein of 654 aa, and ORF3 encodes a functionally unknown phosphoprotein of 108 aa.