Specificity varies with the source and with the activating metal ion. The enzyme from some sources may be identical with EC 3.1.3.1 (alkaline phosphatase) or EC 3.1.3.9 (glucose-6-phosphatase). cf. EC 7.1.3.1, H+-exporting diphosphatase.
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SYSTEMATIC NAME
IUBMB Comments
diphosphate phosphohydrolase
Specificity varies with the source and with the activating metal ion. The enzyme from some sources may be identical with EC 3.1.3.1 (alkaline phosphatase) or EC 3.1.3.9 (glucose-6-phosphatase). cf. EC 7.1.3.1, H+-exporting diphosphatase.
substrate specificity, overview. The enzyme is highly specific, no or poor activity with ribose-5-phosphate, phospho-L-serine, o-phosphocholine, phosphoenolpyruvate, L-glycerol-3-phosphate, beta-glycerol-phosphate, and phospho-L-tyrosine
substrate specificity, overview. The enzyme is highly specific, no or poor activity with ribose-5-phosphate, phospho-L-serine, o-phosphocholine, phosphoenolpyruvate, L-glycerol-3-phosphate, beta-glycerol-phosphate, and phospho-L-tyrosine
dependent on, can be partially substituted by Mn2+, both isozymes show similar catalytic constants and affinities for the Mg-pyrophosphate complex, while differed in their affinity for free Mg2+,
ordered binding of free Mg2+ and of the Mg-diphosphate complex. Both isozymes show similar catalytic constants and affinities for the Mg-diphosphate complex, while differed in their affinity for free Mg2+, kinetics, overview
the N-terminal peptide of immature AtPPA1 is mostly disordered. It can be cleaved during maturation. The cleaved peptide is a mitochondrial targeting signal
the vacuolar H+-translocating pyrophosphatase (H+-PPase) loss-of-function fugu5 mutant is susceptible to drought and displays pleotropic postgerminative growth defects due to excess diphosphate. Stomatal closure after abscisic acid (ABA) treatment is delayed in vhp1-1, a fugu5 allele. In contrast, specific removal of diphosphate rescues all of the above fugu5 developmental and growth defects. Hydrolysis of PPi within guard cells alleviates delayed growth in fugu5-1. The GC1 promoter is properly expressed in guard cells in the fugu5-1 background. Stomatal development is mildly affected in fugu5-1. Dysfunction of H+-PPase in the fugu5 mutant leads to elevated cytosolic PPi levels and results in a pleiotropic phenotype. Mutant fugu5 plants exhibit seasonal fluctuations, growing better during the humid summer but exhibiting susceptibility to the dry winter. Recombinant expression of IPP1 in the guard cells of the pGC1::IPP1/fugu5-1 lines does not affect the palisade cell phenotype. Effect of pGC1::IPP1 expression on palisade tissue development and hypocotyl elongation, overview
tight control of AtPPsPase1 gene expression underlines its important role in the phosphate starvation response, cleavage of diphosphate is an immediate metabolic adaptation reaction
inorganic diphosphatases (PPases), which hydrolyze inorganic diphosphate to phosphate in the presence of divalent metal cations, play a key role in maintaining phosphorus homeostasis in cells
the H+-PPase contributes to stomatal functioning not only as a proton pump that acidifies the vacuoles, but also as an enzyme that maintains adequate PPi levels within guard cells. Regulation of PPi levels by H+-PPase is critical for proper resumption of postgerminative plant development. Diphosphate homeostasis is important for stomatal closure. Stomatal opening is independent of H+-PPase, but a balance between PPi level and vacuolar membrane potential is required for proper regulation of stomata, excess PPi selectively affects stomatal closure movement
topology and conformation of the PPA1 subunits, comparison to the enzyme from Medicago truncatula. The N-terminal peptide of immature AtPPA1 is mostly disordered
topology and conformation of the PPA1 subunits, comparison to the enzyme from Medicago truncatula. The N-terminal peptide of immature AtPPA1 is mostly disordered
the N-terminal peptide is autocatalytically cleaved, presence of three N-terminal variants, truncated at Leu23, Ser25 and Leu26. The growth of AtPPA1 crystal iis strongly correlated with the progression of proteolysis
purified recombinant enzyme, hanging drop vapor diffusion method, mixing of 7.5-10 mg/ml protein with precipitant solution containing 100 mM succinic acid, pH 7.0, and 15% PEG3350, or 100 mM bicine, pH 9.0, 7% PEG 6000, and 3 mM MgCl2 for the Mg2+-bound enzyme, 2 weeks, 19°C, 20% glycerol or PEG400 as cryoprotectants, X-ray diffraction structure determination and analysis at 1.93 A and 1.83 A resolution, respectively, structure modelling. Growth of AtPPA1 crystal is strongly correlated with the progression of proteolysis
construction of the vacuolar H+-translocating pyrophosphatase (H+-PPase) loss-of-function fugu5 mutant that is susceptible to drought and displays pleotropic postgerminative growth defects due to excess diphosphate. Specific removal of PPi from a fugu5 mutant background (i.e. in the pAVP1::IPP1 transgenic line) rescues all recognized developmental defects and vigorously enhances growth. The GC1 promoter is properly expressed in guard cells in the fugu5-1 background. Construction and phenotypic analyses of the pGC1::IPP1 line in the fugu5-1 background expressing the soluble PPase from Saccharomyces cerevisiae strain 288c. pGC1::IPP1/fugu5-1 displays typical oblong cotyledons reminiscent of fugu5 mutants, but expression of IPP1 in the guard cells of the pGC1::IPP1/fugu5-1 lines does not affect the palisade cell phenotype, phenotypes, overview
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli by nickel affinity chromatography, dialysis, tag cleavage by TEV protease, followed by gel filtration and ultrafiltration