Expression and Biochemical Characterization of a Yersinia intermedia Phytase Expressed in Escherichia coli

2019 ◽  
Vol 10 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Mariana S. Vieira ◽  
Vinícius V. Pereira ◽  
Alice da Cunha Morales Álvares ◽  
Lais M. Nogueira ◽  
William J.N. Lima ◽  
...  

Background: Phytases are enzymes capable of degrading phytic acid and used in animal feed supplementation in order to improve digestibility through the release of minerals such as phosphorus. Objective: The main goal of this study was to express and characterize a Yersinia intermedia phytase expressed in Escherichia coli cells. Methods: The Y. intermedia phytase gene was synthesized and overexpressed in Escherichia coli cells. The phytase recombinante (rPHY) was purified to homogeneity using a Ni-NTA column. The biochemical and biophysical properties of the rPHY were measured in order to fully characterize the recombinant enzyme. The following patents database were consulted: Espacenet, USPTO, LATIPAT, Patent Scope, WIPO and Google Patents. Results: The results showed that the rPHY is active at 37-40ºC and presented an optimal pH and temperature of 8.0 and 40°C, respectively. The phytase rPHY was activated by Cu2+ ion and showed resistance to trypsin and pepsin, retaining 55% of the activity at the ratio of 0.02. Furthermore, the dissociation constant (Kd = 1.1150 ± 0.0087 mM), as estimated by a fluorescence binding assay, suggests a medium affinity of the enzyme with the substrate. Conclusion: The results of this article can be considered as innovative and for this reason, they were protected by Intellectual Property Law in Brazil. Take together, the biochemical properties of the rPHY could be useful in future for its industrial application of this enzyme as an additive in the monogastric feed.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Peixian Bai ◽  
Liyuan Wang ◽  
Kang Wei ◽  
Li Ruan ◽  
Liyun Wu ◽  
...  

Abstract Background Alanine decarboxylase (AlaDC), specifically present in tea plants, is crucial for theanine biosynthesis. Serine decarboxylase (SDC), found in many plants, is a protein most closely related to AlaDC. To investigate whether the new gene AlaDC originate from gene SDC and to determine the biochemical properties of the two proteins from Camellia sinensis, the sequences of CsAlaDC and CsSDC were analyzed and the two proteins were over-expressed, purified, and characterized. Results The results showed that exon-intron structures of AlaDC and SDC were quite similar and the protein sequences, encoded by the two genes, shared a high similarity of 85.1%, revealing that new gene AlaDC originated from SDC by gene duplication. CsAlaDC and CsSDC catalyzed the decarboxylation of alanine and serine, respectively. CsAlaDC and CsSDC exhibited the optimal activities at 45 °C (pH 8.0) and 40 °C (pH 7.0), respectively. CsAlaDC was stable under 30 °C (pH 7.0) and CsSDC was stable under 40 °C (pH 6.0–8.0). The activities of the two enzymes were greatly enhanced by the presence of pyridoxal-5′-phosphate. The specific activity of CsSDC (30,488 IU/mg) was 8.8-fold higher than that of CsAlaDC (3467 IU/mg). Conclusions Comparing to CsAlaDC, its ancestral enzyme CsSDC exhibited a higher specific activity and a better thermal and pH stability, indicating that CsSDC acquired the optimized function after a longer evolutionary period. The biochemical properties of CsAlaDC might offer reference for theanine industrial production.


1985 ◽  
Vol 22 (4) ◽  
pp. 375-386 ◽  
Author(s):  
H. C. Wimberly ◽  
D. O. Slauson ◽  
N. R. Neilsen

Antigen-specific challenge of equine leukocytes induced the non-lytic release of a platelet-activating factor in vitro. The equine platelet-activating factor stimulated the release of serotonin from equine platelets in a dose-responsive manner, independent of the presence of cyclo-oxygenase pathway inhibitors such as indomethacin. Rabbit platelets were also responsive to equine platelet-activating factor. The release of equine platelet-activating factor was a rapid reaction with near maximal secretion taking place in 30 seconds. Addition of equine platelet-activating factor to washed equine platelets stimulated platelet aggregation which could not be inhibited by the presence of aspirin or indomethacin. Platelets preincubated with equine platelet-activating factor became specifically desensitized to equine platelet-activating factor while remaining responsive to other platelet stimuli such as collagen and epinephrine. The following biochemical properties of equine platelet-activating factor are identical to those properties of 1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (AGEPC): stability upon exposure to air and acid; loss of functional activity after basecatalyzed methanolysis with subsequent acylation that returned all functional activity; and identical relative mobilities on silica gel G plates developed with chloroform:methanol:water (65:35:6, volume/volume). The combined functional and biochemical characteristics of equine platelet-activating factor strongly suggest identity between this naturally occurring, immunologically derived equine factor and AGEPC.


2008 ◽  
Vol 38 (9) ◽  
pp. 871-876 ◽  
Author(s):  
Alessandra Paglino ◽  
Fabrizio Lombardo ◽  
Bruno Arcà ◽  
Menico Rizzi ◽  
Franca Rossi

2018 ◽  
Author(s):  
Krithika Rajagopalan ◽  
Jonathan Dworkin

AbstractIn bacteria, signaling phosphorylation is thought to occur primarily on His and Asp residues. However, phosphoproteomic surveys in phylogenetically diverse bacteria over the past decade have identified numerous proteins that are phosphorylated on Ser and/or Thr residues. Consistently, genes encoding Ser/Thr kinases are present in many bacterial genomes such asE. coli,which encodes at least three Ser/Thr kinases. Since Ser/Thr phosphorylation is a stable modification, a dedicated phosphatase is necessary to allow reversible regulation. Ser/Thr phosphatases belonging to several conserved families are found in bacteria. One family of particular interest are Ser/Thr phosphatases which have extensive sequence and structural homology to eukaryotic Ser/Thr PP2C phosphatases. These proteins, called eSTPs (eukaryotic-like Ser/Thr phosphatases), have been identified in a number of bacteria, but not inE. coli.Here, we describe a previously unknown eSTP encoded by anE. coliORF,yegK,and characterize its biochemical properties including its kinetics, substrate specificity and sensitivity to known phosphatase inhibitors. We investigate differences in the activity of this protein in closely relatedE. colistrains. Finally, we demonstrate that this eSTP acts to dephosphorylate a novel Ser/Thr kinase which is encoded in the same operon.ImportanceRegulatory protein phosphorylation is a conserved mechanism of signaling in all biological systems. Recent phosphoproteomic analyses of phylogenetically diverse bacteria including the model Gram-negative bacteriumE. colidemonstrate that many proteins are phosphorylated on serine or threonine residues. In contrast to phosphorylation on histidine or aspartate residues, phosphorylation of serine and threonine residues is stable and requires the action of a partner Ser/Thr phosphatase to remove the modification. Although a number of Ser/Thr kinases have been reported inE. coli, no partner Ser/Thrphosphatases have been identified. Here, we biochemically characterize a novel Ser/Thr phosphatase that acts to dephosphorylate a Ser/Thr kinase that is encoded in the same operon.


2018 ◽  
Vol 43 (6) ◽  
pp. 638-650
Author(s):  
Ruth Ololade Amiola ◽  
Adedeji Nelson Ademakinwa ◽  
Zainab Adenike Ayinla ◽  
Esther Nkechi Ezima ◽  
Femi Kayode Agboola

Abstract Background β-Cyanoalanine synthase plays essential roles in germinating seeds, such as in cyanide homeostasis. Methods β-Cyanoalanine synthase was isolated from sorghum seeds, purified using chromatographic techniques and its biochemical and catalytic properties were determined. Results The purified enzyme had a yield of 61.74% and specific activity of 577.50 nmol H2S/min/mg of protein. The apparent and subunit molecular weight for purified β-cyanoalanine synthase were 58.26±2.41 kDa and 63.4 kDa, respectively. The kinetic parameters with sodium cyanide as substrate were 0.67±0.08 mM, 17.60±0.50 nmol H2S/mL/min, 2.97×10−1 s−1 and 4.43×102 M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively. With L-cysteine as substrate, the kinetic parameters were 2.64±0.37 mM, 63.41±4.04 nmol H2S/mL/min, 10.71×10−1 s−1 and 4.06×102 M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively. The optimum temperature and pH for activity were 35°C and 8.5, respectively. The enzyme retained more than half of its activity at 40°C. Inhibitors such as HgCl2, EDTA, glycine and iodoacetamide reduced enzyme activity. Conclusion The biochemical properties of β-cyanoalanine synthase in germinating sorghum seeds highlights its roles in maintaining cyanide homeostasis.


2005 ◽  
Vol 187 (22) ◽  
pp. 7696-7702 ◽  
Author(s):  
Xiaoli Gao ◽  
Chew Ling Tan ◽  
Chew Chieng Yeo ◽  
Chit Laa Poh

ABSTRACT The xlnD gene from Pseudomonas alcaligenes NCIMB 9867 (strain P25X) was shown to encode 3-hydroxybenzoate 6-hydroxylase I, the enzyme that catalyzes the NADH-dependent conversion of 3-hydroxybenzoate to gentisate. Active recombinant XlnD was purified as a hexahistidine fusion protein from Escherichia coli, had an estimated molecular mass of 130 kDa, and is probably a trimeric protein with a subunit mass of 43 kDa. This is in contrast to the monomeric nature of the few 3-hydroxybenzoate 6-hydroxylases that have been characterized thus far. Like other 3-hydroxybenzoate 6-hydroxylases, XlnD could utilize either NADH or NADPH as the electron donor. P25X harbors a second 3-hydroxybenzoate 6-hydroxylase II that was strictly inducible by specific aromatic substrates. However, the degradation of 2,5-xylenol and 3,5-xylenol in strain P25X was found to be dependent on the xlnD-encoded 6-hydroxylase I and not the second, strictly inducible 6-hydroxylase II.


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