Inorganic Pyrophosphatase in Storage Buffer

2013 ◽  
Vol 2013 (11) ◽  
pp. pdb.rec079392-pdb.rec079392
2019 ◽  
Vol 476 (16) ◽  
pp. 2297-2319 ◽  
Author(s):  
Marta Grzechowiak ◽  
Milosz Ruszkowski ◽  
Joanna Sliwiak ◽  
Kamil Szpotkowski ◽  
Michal Sikorski ◽  
...  

Abstract Inorganic pyrophosphatases (PPases, EC 3.6.1.1), which hydrolyze inorganic pyrophosphate to phosphate in the presence of divalent metal cations, play a key role in maintaining phosphorus homeostasis in cells. DNA coding inorganic pyrophosphatases from Arabidopsis thaliana (AtPPA1) and Medicago truncatula (MtPPA1) were cloned into a bacterial expression vector and the proteins were produced in Escherichia coli cells and crystallized. In terms of their subunit fold, AtPPA1 and MtPPA1 are reminiscent of other members of Family I soluble pyrophosphatases from bacteria and yeast. Like their bacterial orthologs, both plant PPases form hexamers, as confirmed in solution by multi-angle light scattering and size-exclusion chromatography. This is in contrast with the fungal counterparts, which are dimeric. Unexpectedly, the crystallized AtPPA1 and MtPPA1 proteins lack ∼30 amino acid residues at their N-termini, as independently confirmed by chemical sequencing. In vitro, self-cleavage of the recombinant proteins is observed after prolonged storage or during crystallization. The cleaved fragment corresponds to a putative signal peptide of mitochondrial targeting, with a predicted cleavage site at Val31–Ala32. Site-directed mutagenesis shows that mutations of the key active site Asp residues dramatically reduce the cleavage rate, which suggests a moonlighting proteolytic activity. Moreover, the discovery of autoproteolytic cleavage of a mitochondrial targeting peptide would change our perception of this signaling process.


1972 ◽  
Vol 70 (4) ◽  
pp. 676-682 ◽  
Author(s):  
Cipora Streifler ◽  
Arie Orenstein ◽  
Arieh Harell

ABSTRACT The influence of thyrocalcitonin (TCT) on the enzymes alkaline phosphatase and inorganic pyrophosphatase in rat bone, kidney and intestine was studied. The rats were injected with TCT every hour for 4 hours. They were divided into groups and were sacrificed 1 h after the first, second, third and fourth injection respectively. The plasma calcium was found to be reduced. Enzyme studies showed that: a) in tibia metaphysis homogenates alkaline phosphatase increased in response to TCT, to 198, 175, 154 and 183 per cent of the non-injected rats after 1, 2, 3, and 4 injections, respectively; inorganic pyrophosphatase was elevated to 356, 209, 221, 425 per cent after the same TCT injections. b) In kidney homogenates alkaline phosphatase was reduced to 75, 53, 79, 68 per cent of the non-injected rats after 1, 2, 3 and four doses, respectively; inorganic pyrophosphatase was reduced to 78, 56, 77 and 71 per cent after the same injections of TCT. c) In the jejunum, alkaline phosphatase was found to be 88.5, 71, 91 and 115 per cent of the untreated rats after 1, 2, 3 and 4 injections, respectively; pyrophosphatase in this tissue was found to be 105, 102, 102 and 113 per cent of the normal under the above conditions. The results indicate: 1. TCT causes increases in alkaline phosphatase and inorganic pyrophosphatase activities in bone. The increase of pyrophosphatase is significantly more marked than the increase of alkaline phosphatase; 2. in kidney tissue, the action of TCT on these two enzymes is slower and their activities are equally reduced; 3. in the jejunum no significant effect of TCT on the activity of these two enzymes was observed.


2009 ◽  
Vol 191 (10) ◽  
pp. 3415-3419 ◽  
Author(s):  
Hyun Sook Lee ◽  
Yun Jae Kim ◽  
Jung-Hyun Lee ◽  
Sung Gyun Kang

ABSTRACT Two hypothetical genes were functionally verified to be a pyrophosphatase and a PAP phosphatase in Thermococcus onnurineus NA1. This is the first report of the pyrophosphatases and the PAP phosphatases being organized in the gene clusters of the sulfate activation system only in T. onnurineus NA1 and “Pyrococcus abyssi.”


1970 ◽  
Vol 245 (17) ◽  
pp. 4358-4364 ◽  
Author(s):  
Pamela M. Burton ◽  
John Josse

1975 ◽  
Vol 23 (5) ◽  
pp. 342-347 ◽  
Author(s):  
A Linde ◽  
B C Magnusson

The effects of the alkaline phosphatase inhibitors levamisole and R 8231 on p-nitro-phenylphosphatase, inorganic pyrophosphatase and adenosine triphosphatase (ATPase) activities in dentingenically active odontoblasts were studied. The p-nitrophenylphosphatase and inorganic pyrophosphatase activities were inhibited, while 40% of the ATP-splitting enzyme activity remained under the assay condition used. This finding, togeather with earlier studies, indicates that at least two different phosphatase are active at alkaline pH in hard tissue-forming cells; on nonspecific alkaline phosphatase and one specific ATPase. The ATPase activity is uninfluenced by ouabain and ruthenium red and is activated by Ca-2+ ions.


2010 ◽  
Vol 43 (5) ◽  
pp. 1113-1120 ◽  
Author(s):  
Esko Oksanen ◽  
François Dauvergne ◽  
Adrian Goldman ◽  
Monika Budayova-Spano

H atoms play a central role in enzymatic mechanisms, but H-atom positions cannot generally be determined by X-ray crystallography. Neutron crystallography, on the other hand, can be used to determine H-atom positions but it is experimentally very challenging. Yeast inorganic pyrophosphatase (PPase) is an essential enzyme that has been studied extensively by X-ray crystallography, yet the details of the catalytic mechanism remain incompletely understood. The temperature instability of PPase crystals has in the past prevented the collection of a neutron diffraction data set. This paper reports how the crystal growth has been optimized in temperature-controlled conditions. To stabilize the crystals during neutron data collection a Peltier cooling device that minimizes the temperature gradient along the capillary has been developed. This device allowed the collection of a full neutron diffraction data set.


Sign in / Sign up

Export Citation Format

Share Document