Protein phosphatases 1, 2A, and 2C are protein histidine phosphatases.
Eukaryotic cellular proteins contain phosphohistidine. To search for protein histidine phosphatases, protein histidine kinase from Saccharomyces cerevisiae was used to phosphorylate histone H4 on histidine at position 75 in the H4 amino acid sequence. Incubation of the phosphorylated histone H4 with either protein phosphatase 1, 2A, or 2C resulted in extensive removal of phosphate from the phosphorylated histone. Thus, protein phosphatases 1, 2A, and 2C are histidine phosphatases as well as serine/threonine phosphatases. Calcium/calmodulin-regulated protein phosphatase (protein phosphatase 2B) did not remove phosphate from phosphohistidine. The histidine phosphatase reaction was tested for a magnesium requirement and effects of inhibitor-1 and okadaic acid. In all cases, the protein phosphatases behaved as they do in their serine/threonine phosphatase activity. Extracts of the yeast, S. cerevisiae, contain protein histidine phosphatase activity. Quantitative measurement of phosphatase activity shows that the activity against phosphohistidine is a major activity of protein phosphatases 1, 2A, and 2C.
Department of Biological Chemistry, University of California, Davis 95616.
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D002352:Carrier Proteins; D004988:Ethers, Cyclic / Q000494:pharmacology; D006639:Histidine / Q000031:analogs & derivatives / Q000378:metabolism*; D000071677:Histidine Kinase; D006657:Histones / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D054645:Protein Phosphatase 1; D011506:Proteins / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D014462:Ultrafiltration
D002352:Carrier Proteins; D004988:Ethers, Cyclic; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; C021042:protein phosphatase inhibitor-1; D019319:Okadaic Acid; D006639:Histidine; D011494:Protein Kinases; D000071677:Histidine Kinase; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D008274:Magnesium; C005436:phosphohistidine