| Autor: |
Lila Patrikainen, H. Kalervo Väänänen, Pirkko Vihko, Sari L. Alatalo, Helena Kaija |
| Rok vydání: |
2006 |
| Předmět: |
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| Zdroj: |
Dynamics of Bone and Cartilage Metabolism (Second Edition) |
| DOI: |
10.1016/b9-78-012088-5/62650-011x |
| Popis: |
Phosphatases can be classified according to several frameworks. They can be divided into groups based on their substrate type. Nonspecific phosphatases catalyze the hydrolysis of almost any phosphate ester, whereas protein phosphatases prefer phosphoproteins or phosphopeptides as substrates. Nonspecific phosphatases can be divided into alkaline phosphatases and acid phosphatases based on their optimal pH for catalysis. One obvious difference among phosphatases is the presence or absence of metal ion cofactors. Acid phosphatases have wide substrate specificity and some of them catalyze transphosphorylations between phosphoesters and alcohols. Nonspecific acid phosphatases recycle phosphate in metabolic reactions. Protein phosphatases are a structurally miscellaneous group of enzymes that remove phosphate groups that have been attached to amino acid residues of proteins by protein kinases. Protein phosphatases have different mechanisms of action, subcellular localization, and substrate specificity with varied demands for optimal pH. Protein phosphatases comprise two groups based upon their substrate specificity. Protein–tyrosine phosphatases prefer to remove phosphate from tyrosine residue, and serine/threonine protein phosphatases from serine or threonine residue. The PTPase group includes dual specificity phosphatases, which are capable of hydrolyzing phosphorylated tyrosine, serine, and threonine, and phosphorylated lipids. Protein phosphatases regulate signal transduction pathways. Approximately 30% of intracellular proteins are subject to reversible protein phosphorylation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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