Fungal trehalose phosphorylase: kinetic mechanism, pH-dependence of the reaction and some structural properties of the enzyme from Schizophyllum commune

2001 ◽  
Vol 356 (3) ◽  
pp. 757-767 ◽  
Author(s):  
Christian EIS ◽  
Mark WATKINS ◽  
Thomas PROHASKA ◽  
Bernd NIDETZKY
Keyword(s):  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Ph Dependence ◽  
Schizophyllum Commune ◽  
Structural Similarity ◽  
Kinetic Mechanism ◽  
Inductively Coupled ◽  
Peptide Mass ◽  
Dead End ◽  
Trehalose Phosphorylase

Initial-velocity measurements for the phospholysis and synthesis of α,α-trehalose catalysed by trehalose phosphorylase from Schizophyllum commune and product and dead-end inhibitor studies show that this enzyme has an ordered Bi Bi kinetic mechanism, in which phosphate binds before α,α-trehalose, and α-d-glucose is released before α-d-glucose 1-phosphate. The free-energy profile for the enzymic reaction at physiological reactant concentrations displays its largest barriers for steps involved in reverse glucosyl transfer to d-glucose, and reveals the direction of phospholysis to be favoured thermodynamically. The pH dependence of kinetic parameters for all substrates and the dissociation constant of d-glucal, a competitive dead-end inhibitor against d-glucose (Ki = 0.3mM at pH6.6 and 30°C), were determined. Maximum velocities and catalytic efficiencies for the forward and reverse reactions decrease at high and low pH, giving apparent pK values of 7.2–7.8 and 5.5–6.0 for two groups whose correct protonation state is required for catalysis. The pH dependences of kcat/K are interpreted in terms of monoanionic phosphate and α-d-glucose 1-phosphate being the substrates, and of the pK value seen at high pH corresponding to the phosphate group in solution or bound to the enzyme. The Ki value for the inhibitor decreases outside the optimum pH range for catalysis, indicating that binding of d-glucal is tighter with incorrectly ionized forms of the complex between the enzyme and α-d-glucose 1-phosphate. Each molecule of trehalose phosphorylase contains one Mg2+ that is non-dissociable in the presence of metal chelators. Measurements of the 26Mg2+/24Mg2+ ratio in the solvent and on the enzyme by using inductively coupled plasma MS show that exchange of metal ion between protein and solution does not occur at measurable rates. Tryptic peptide mass mapping reveals close structural similarity between trehalose phosphorylases from basidiomycete fungi.

scholarly journals In vitro Antimicrobial Effects of Virus Block, Which Contains Multiple Polyoxometalate Compounds, and Hygienic Effects of Virus Block-Supplemented Moist Hand Towels

Pharmacology ◽  
2019 ◽  
Vol 104 (1-2) ◽  
pp. 98-112 ◽  
Author(s):  
Katsuaki Dan ◽  
Naohiro Katoh ◽  
Takaaki Matsuoka ◽  
Katsuyuki Fujinami
Keyword(s):  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Bacterial Flora ◽  
Atomic Emission ◽  
Time Dependent ◽  
Antimicrobial Effects ◽  
Inductively Coupled ◽  
Before And After ◽  
Normal Bacterial Flora

Background: Historical evidence has verified the multifaceted antiviral efficacy of polyoxometalates (PMs). Methods: We carried out a study to investigate the antimicrobial effects of each of the 5 substances comprising virus block (VB): 3 PMs that have antibacterial and antiviral activity, an antibiotic agent, and an antibacterial agent. We also investigated the effectiveness of the addition of VB to moist hand towels in a study involving 120 volunteers. The time-dependent changes in metal ion concentrations in aqueous VB solution were analyzed using inductively coupled plasma atomic emission spectroscopy. Results: The metal elements in the aqueous VB solution remained stable for 12 weeks without undergoing time-dependent changes. Discussion: Further investigations were performed to study hand hygiene using moist hand towels in daily life settings. To this end, 120 volunteers provided 240 specimens that were used to investigate the presence of antibacterial compounds on the volunteers’ hands before and after hand towel use. An aliquot of each specimen was suspended in phosphate-buffered saline and plated on agar media, and the number of colonies formed was counted. Normal bacterial flora found on the hands of the volunteers was investigated before and after the use of 4 different moist hand towels. Conclusions: The effects of VB and PMs were superior to those of commercial moist hand towels, indicating that effective data were obtained that may be useful for the practical application of the tested items.

Metal Ion Release and Cytotoxicity of Titanium Orthodontic Miniscrews

2017 ◽  
Vol 730 ◽  
pp. 141-147
Author(s):  
Katha Kosayadiloka ◽  
Nathaphon Tangjit ◽  
Suwannee Luppanapornlarp ◽  
Peerapong Santiwong
Keyword(s):  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
The Self ◽  
Cytotoxicity Test ◽  
Ion Release ◽  
Element Analysis ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Metal Ion Release ◽  
Plasma Mass Spectrometry

The aim of this study was to investigate the metal ion release and cytotoxicity of MU orthodontic miniscrews as well as two other brands of orthodontic miniscrews over time. Twenty-four orthodontic miniscrews were tested, divided into three groups of eight. Each sample extraction was performed following the ISO 10993-12:2012 method. Solutions were collected after 1, 7, and 30 days (T1, T2, and T3). The supernatants extracted from these three groups were added and exposed to mouse L929 fibroblastic cell line using an MTT cytotoxicity test. They were also tested for ion release by inductively coupled plasma-mass spectrometry (ICP-MS). Element analysis by energy-dispersive X-ray spectroscopy (EDS) was used to analyze the surfaces of the miniscrews. The quantification of three elements, namely, titanium (Ti), aluminum (Al), and vanadium (V) were assessed. The results indicated that there were no statistical differences between the self-made orthodontic miniscrews and those from two commercial groups (p<0.05). Throughout the testing period, the quantity of ions increased from T1 to T3. After 24 h, vanadium was the first to appear on the surface in small quantities in other two commercial groups. The self-made orthodontic miniscrews exhibited no toxic effects on living cells.

scholarly journals The influence of different compounds of trace elements on the biomass and synthesis of exopolysaccharides of mycelium Trametes versicolor (Polyporaceae, Polyporales)

2017 ◽  
Vol 25 (4) ◽  
Author(s):  
G. A. Al-Maali
Keyword(s):  
Trace Elements ◽  
Copper Sulfate ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Trametes Versicolor ◽  
Copper Ions ◽  
Optical Emission ◽  
Nitrogen Sources ◽  
Physiological Indicators ◽  
Inductively Coupled

This article presents the results of research on the influence of citrates of zinc, manganese and copper, obtained by the method of aquanotechnology, on a number of physiological indicators of a valuable medicinal mushroom Trametes versicolor 353. Previously we detected that these metal citrates stimulated the growth of mycelium more intensively than sulfates of the above-mentioned metals in equal concentrations. In the present research we investigated the influence of these metal citrates on the parameters of assimilation of carbon and nitrogen sources, metal ion accumulation and synthesis of exopolysaccharides. The degree of metals ions accumulation in the mycelium was studied by the  method of optical emission spectroscopy with an inductively coupled plasma. The economic coefficient of biomass synthesis and impact of nitrogen assimilation were higher on media with the metals citrate than on the medium with the sulfates of the studied metals. Thus, the highest economic coefficient of biomass synthesis (36%) was observed on the medium with copper citrate. Also, copper citrate (amongst the studied metals) increased the level of assimilation of the nitrogen source by up to 35%, versus 18% on the control medium. Quantitative analysis of trace elements in biomass showed that the mycelium accumulated an equal amount of zinc or manganese ions on both types of media (with citrate or sulfate of these metals). However, on the medium with copper citrate, mycelium of T. versicolor 353 accumulated copper ions better then on a medium with copper sulfate: 82.9 μg/g of biomass on the medium with copper sulfate versus 162.0 μg/g of biomass on the medium with copper citrate. Also the results show that a significant increase of biomass (by 79% relative to the control) on the copper citrate medium is due to a threefold reduction of the exopolysaccharides amount. This data indicates a greater biological activity of copper citrate,  relative to copper sulfate. Only zinc citrate raised both the synthesis of biomass and the synthesis of exopolysaccharides by 37% and 29% respectively ( relative to the control trial).

scholarly journals Metal ions leachables from fake orthodontic braces incubated in simulated body fluid

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Riyam Haleem ◽  
Noor Ayuni Ahmad Shafiai ◽  
Siti Noor Fazliah Mohd Noor
Keyword(s):  
Simulated Body Fluid ◽  
Metal Ions ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Body Fluid ◽  
Atomic Emission ◽  
Analysis Data ◽  
Inductively Coupled ◽  
Significant Release ◽  
Control Samples

Abstract Background The demand for fake braces usage in Southeast Asia are increasing but lack of certification and information on fake braces as medical devices from regulated bodies raised a concern towards its safety. The aim of this study was to determine the types of metal ion leachable from removable fake braces based on heavy metal ions present in metallic materials, immersed in simulated body fluid (SBF) and analysed using inductively coupled plasma atomic emission spectroscopy. Methods Three sets of fake braces and one control were dissembled to only their brackets and archwires and immersed separately in SBF. They were placed in an incubator shaker at a temperature of 37 °C at 50 rpm. A 3.0 ml measurement of SBF was taken out from the sample containers at days 7, 14 and 28 and kept at − 20 °C for further analysis. Data were analysed using SPSS version 26.0 (IBM, Armonk, USA) (P < 0.05). Descriptive and one-way ANOVA analyses with Bonferroni post hoc tests were used to assess the significant differences between the metal ions released in SBF from the control samples and fake braces. Results All 23 elements under investigation except Si ions were detected from the control samples and fake braces. There were significant increased K ions and reduced levels of Mg ions from the fake archwires and brackets. Most ions released were less than 10 mg/L (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Pb, Al) or 1 mg/L (Li, Ba) into the SBF medium. Conclusion There were significant release of Ca and K ions from the fake samples. Elements such as Li, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd and Sb had increased in concentration at day 7 and the concentration plateaued until day 28.

scholarly journals The Protein Phosphatases of Synechocystis sp. Strain PCC 6803: Open Reading Frames sll1033 and sll1387 Encode Enzymes That Exhibit both Protein-Serine and Protein-Tyrosine Phosphatase Activity In Vitro

2005 ◽  
Vol 187 (17) ◽  
pp. 5877-5884 ◽  
Author(s):  
Renhui Li ◽  
M. Ben Potters ◽  
Liang Shi ◽  
Peter J. Kennelly
Keyword(s):  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Protein Phosphatases ◽  
Tyrosine Phosphatase ◽  
Maximal Activity ◽  
Open Reading Frames ◽  
Inductively Coupled ◽  
Reading Frames ◽  
Pcc 6803

ABSTRACT The open reading frames (ORFs) encoding two potential protein-serine/threonine phosphatases from the cyanobacterium Synechocystis sp. strain PCC 6803 were cloned and their protein products expressed in Escherichia coli cells. The product of ORF sll1033, SynPPM3, is a homologue of the PPM family of protein-serine/threonine phosphatases found in all eukaryotes as well as many members of the Bacteria. Surprisingly, the recombinant protein phosphatase dephosphorylated phosphotyrosine- as well as phosphoserine-containing proteins in vitro. While kinetic analyses indicate that the enzyme was more efficient at dephosphorylating the latter, replacement of Asp608 by asparagine enhanced activity toward a phosphotyrosine-containing protein fourfold. The product of ORF sll1387, SynPPP1, is the sole homolog of the PPP family of protein phosphatases encoded by the genome of Synechocystis sp. strain PCC 6803. Like many other bacterial PPPs, the enzyme dephosphorylated phosphoserine- and phosphotyrosine-containing proteins with comparable efficiencies. However, while previously described PPPs from prokaryotic organisms required the addition of exogenous metal ion cofactors, such as Mg2+ or Mn2+, for activity, recombinantly produced SynPPP1 displayed near-maximal activity in the absence of added metals. Inductively coupled plasma mass spectrometry indicated that recombinant SynPPP1 contained significant quantities, 0.32 to 0.44 mol/mole total, of Mg and Mn. In this respect, the cyanobacterial enzyme resembled eukaryotic members of the PPP family, which are metalloproteins. mRNA encoding SynPPP1 or SynPPM3 could be detected in cells grown under many, but not all, environmental conditions.

Analysis of metal ion impurities in liquid crystals using high resolution inductively coupled plasma mass spectrometry

2012 ◽  
Vol 4 (11) ◽  
pp. 3631 ◽  
Author(s):  
Huan-Yi Hung ◽  
Chien-Wei Lu ◽  
Cheng-Yu Lee ◽  
Chain-Shu Hsu ◽  
You-Zung Hsieh
Keyword(s):  
Mass Spectrometry ◽  
Liquid Crystals ◽  
High Resolution ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Considerations of inductively coupled plasma mass spectrometry techniques for characterizing the dissolution of metal-based nanomaterials in biological tissues

2015 ◽  
Vol 30 (8) ◽  
pp. 1689-1705 ◽  
Author(s):  
Cheng-Kuan Su ◽  
Yuh-Chang Sun
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Biological Systems ◽  
Biological Tissues ◽  
Widespread Application ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Toxic Responses ◽  
Ion Species

Dissolution of metal-based nanomaterials (MNMs) leads to the release of metal ion species; this phenomenon is a major concern affecting the widespread application of MNMs because it can affect their subsequent biodistribution patterns and toxic responses toward living biological systems.

Dispersive Liquid–Liquid Microextraction Using Low-Toxic Solvent for the Determination of Heavy Metals in Water Samples by Inductively Coupled Plasma–Mass Spectrometry

2016 ◽  
Vol 99 (1) ◽  
pp. 260-266 ◽  
Author(s):  
Guilong Peng ◽  
Ying Lu ◽  
Qiang He ◽  
Daniel Mmereki ◽  
Guangming Zhou ◽  
...  
Keyword(s):  
Water Samples ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Chlorinated Solvents ◽  
Inductively Coupled ◽  
Real Water Samples ◽  
Low Toxic ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

Abstract A low-toxic dispersive liquid–liquid microextraction (DLLME) combined with inductively coupled plasma-MS was used for preconcentration and determination of Cu, Cr, Cd, Ni, Mn, and Pb in real-water samples. In traditional DLLME analysis, chlorinated solvents have been widely used as extraction solvents. However, these solvents are not environmentally friendly. To overcome this problem, we used a low-toxic bromosolvent (1-bromo-3-methylbutane; lethal concentration, 50%, 6150 mg/kg) as the extraction solvent. To study the effects of different parameters on the extraction efficiency, an orthogonal array experimental design with an L16(45) matrix was used. Under the best experimental conditions (i.e., concentration of complexing reagent 1-(2-pyridylazo)-2-naphthol, 1.5 × 10−3 mol/L; pH, 7.0; volume of acetone, 0.5 mL; volume of 1-bromo-3 methylbutane, 30 μL; and without salt addition), the enhancement factor ranged from 34 to 40. The linear dynamic range was 1–1000 μg/L with r2 values of 0.9984–0.9999, and the LODs were between 0.042 and 0.53 μg/L. RSDs (at metal ion concentrations of 20 μg/L, n = 6) were 2.12 to 3.42%. The developed method was successfully applied to the extraction and determination of the mentioned metal ions in real-water samples, and satisfactory results were obtained.

Sign in / Sign up

Export Citation Format

Share Document