Oxidation of Phenol by Hydrogen Peroxide Catalyzed by Metal-Containing Poly(amidoxime) Grafted Starch

El‐Hamshary, Hany; El‐Newehy, Mohamed H.; Al‐Deyab, Salem S.

doi:10.3390/molecules16129900

Cited by 21 publications

(11 citation statements)

References 31 publications

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“…In a different study, the size of starch granules illuminated by red light for different times have also been measured using SEM scans arriving at similar values [ 32 ]. Interestingly, it has been suggested that smaller starch granules are more easily hydrolyzed into sugars than larger ones, regardless of botanical source [ 33 ]. After 72 h of continuous irradiation, the sizes of starch granules in turions are significantly reduced to about 1.5 μm [ 32 ].…”

Section: Discussionmentioning

confidence: 99%

Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed)

Wang

Messing

2012

BMC Plant Biol

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BackgroundAquatic plants differ in their development from terrestrial plants in their morphology and physiology, but little is known about the molecular basis of the major phases of their life cycle. Interestingly, in place of seeds of terrestrial plants their dormant phase is represented by turions, which circumvents sexual reproduction. However, like seeds turions provide energy storage for starting the next growing season.ResultsTo begin a characterization of the transition from the growth to the dormant phase we used abscisic acid (ABA), a plant hormone, to induce controlled turion formation in Spirodela polyrhiza and investigated their differentiation from fronds, representing their growth phase, into turions with respect to morphological, ultra-structural characteristics, and starch content. Turions were rich in anthocyanin pigmentation and had a density that submerged them to the bottom of liquid medium. Transmission electron microscopy (TEM) of turions showed in comparison to fronds shrunken vacuoles, smaller intercellular space, and abundant starch granules surrounded by thylakoid membranes. Turions accumulated more than 60% starch in dry mass after two weeks of ABA treatment. To further understand the mechanism of the developmental switch from fronds to turions, we cloned and sequenced the genes of three large-subunit ADP-glucose pyrophosphorylases (APLs). All three putative protein and exon sequences were conserved, but the corresponding genomic sequences were extremely variable mainly due to the invasion of miniature inverted-repeat transposable elements (MITEs) into introns. A molecular three-dimensional model of the SpAPLs was consistent with their regulatory mechanism in the interaction with the substrate (ATP) and allosteric activator (3-PGA) to permit conformational changes of its structure. Gene expression analysis revealed that each gene was associated with distinct temporal expression during turion formation. APL2 and APL3 were highly expressed in earlier stages of turion development, while APL1 expression was reduced throughout turion development.ConclusionsThese results suggest that the differential expression of APLs could be used to enhance energy flow from photosynthesis to storage of carbon in aquatic plants, making duckweeds a useful alternative biofuel feedstock.

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Section: Discussionmentioning

confidence: 99%

Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed)

Wang

Messing

2012

BMC Plant Biol

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“…The reaction mixture was incubated for 24 h and then harvested. The IR spectra were recorded in the region 4000-400 cm −1 for the samples in KBr pellets (26). In order to study the biotransformations, 1 mL of the reaction mixture containing 250 μM, H 2 O 2 in 100 mM phosphate buffer pH 7.0 at 30°C, substrate (phenolic compounds) was varied in the range 0.01-0.5 mM and 1.80 IU of the crude enzyme was added.…”

Section: Bioconversion Of Phenolic Compoundsmentioning

confidence: 99%

The role of peroxidase in the enzymatic oxidation of phenolic compounds to quinones fromLuffa aegyptiaca(gourd) fruit juice

Yadav

Rai

Yadav

2017

Green Chemistry Letters and Reviews

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Luffa aegyptiaca fruit juice was used as a low purity source of enzyme, which contained peroxidase activity of 180 IU/mL. The results of UV/VIS and IR studies suggested that L. aegyptiaca fruit juice works efficiently in the enzymatic conversion of phenolic compounds, namely guaiacol, m-cresol, p-cresol, o-cresol, anisole, resorcinol, catechol, pyrogallol, hydroquinone, veratryl alcohol and phoreguicinol to quinones at 30°C. The p-cresol and pyrogallol were converted to quinones more efficiently as compared to other phenolic compounds. Determination of enzymatic characteristic properties such as Michaelis-Menten constant (Km), temperature optima and pH optima using different phenolic compounds, indicated p-cresol as a potential substrate for the peroxidase enzyme assay at room temperature, whereas guaiacol, which is widely used as a substrate for enzyme assay, has a higher temperature optima at 60°C for its maximum catalytic activity. Enzyme activity is inhibited by sodium azide using different phenolic substrates in the reaction mixture.

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“…The grafting of polymethacrylonitrile on a slurry of starch was performed (GP = 0–105%) but no grafting occurred beyond 45°C . Starch‐ graft ‐polyamidoxime was obtained by converting the nitrile groups of the starch‐ graft ‐polyacrylonitrile into amidoximes under basic conditions .…”

Section: Grafting From Via Radical Polymerizationmentioning

confidence: 99%

Modification of starch by graft copolymerization

et al. 2017

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Research toward bio-based and biodegradable polymers has received a lot of attention these last years, due to environmental concerns and the need to replace fossil resources. Starch is in this frame an interesting starting material due to its abundance and low cost. Native starch displays however, poor mechanical properties and is highly hydrophilic. New starch-based thermoplastic materials can be prepared to overcome these drawbacks by chemical modification, and notably graft copolymerization. A large range of polymers can be grafted on starch by ring-opening and radical polymerizations of various monomers in order to modulate the properties of the final product. Polymers can also be directly grafted onto starch using coupling strategies. This review presents the state of the art in the field.

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Oxidation of Phenol by Hydrogen Peroxide Catalyzed by Metal-Containing Poly(amidoxime) Grafted Starch

Cited by 21 publications

References 31 publications

Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed)

Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed)

The role of peroxidase in the enzymatic oxidation of phenolic compounds to quinones fromLuffa aegyptiaca(gourd) fruit juice

Modification of starch by graft copolymerization

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