Quick and sensitive colorimetric detection of amino acid with functionalized-silver/copper nanoparticles in the presence of cross linker, and bacteria detection by using DNA-template nanoparticles as peroxidase activity

2021 ◽  
pp. 120636
Author(s):  
Ashkan Bahadoran ◽  
Mahmoud Khoshnoudi Jabarabadi ◽  
Zaid Hameed Mahmood ◽  
Dmitry Bokov ◽  
Baadal Jushi Janani ◽  
...  
Keyword(s):  
Amino Acid ◽  
Copper Nanoparticles ◽  
Peroxidase Activity ◽  
Colorimetric Detection ◽  
Bacteria Detection ◽  
Silver Copper ◽  
Cross Linker ◽  
Dna Template

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals The catalase-peroxidase of Synechococcus PCC 7942: purification, nucleotide sequence analysis and expression in Escherichia coli

1996 ◽  
Vol 316 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Michinori MUTSUDA ◽  
Takahiro ISHIKAWA ◽  
Toru TAKEDA ◽  
Shigeru SHIGEOKA
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Molecular Mass ◽  
Peroxidase Activity ◽  
Catalase Activity ◽  
Native Enzyme ◽  
Nucleotide Sequence Analysis ◽  
Synechococcus Pcc 7942 ◽  
Catalase Peroxidase ◽  
Pcc 7942

Synechococcus PCC 7942, a cyanobacterium, possesses catalase–peroxidase as the sole hydrogen peroxide-scavenging system. The enzyme has been purified to electrophoretic homogenenity from the cells. The native enzyme had a molecular mass of 150 kDa and was composed of two identical subunits of molecular mass 79 kDa. The apparent Km value of the catalase activity for H2O2 was 4.2±0.27 mM and the kcat value was 2.6×104 s-1. The enzyme contained high catalase activity and an appreciable peroxidase activity with o-dianisidine and pyrogallol. The catalase activity was not inhibited by 3-amino-1,2,4-triazole but by KCN and NaN3 (apparent Ki values 19.3±0.84 and 20.2±0.95 μM respectively). The enzyme showed an absorption spectrum of typical protohaem and contained one protohaem molecule per dimer. The gene encoding catalase–peroxidase was cloned from the chromosomal DNA of Synechococcus PCC 7942. A 2160 bp open reading frame (ORF), coding a catalase–peroxidase of 720 amino acid residues (approx. 79.9 kDa), was observed. The deduced amino acid sequence coincided with that of the N-terminus of the purified enzyme and showed a remarkable similarity to those of a family of catalase–peroxidases of prokaryotic cells. Escherichia coli BL21(DE3)plysS, harbouring a recombinant plasmid containing the catalase–peroxidase gene, produced a large amount of proteins that co-migrated on SDS/PAGE with the native enzyme. The recombinant enzyme showed the same ratio of catalase activity to peroxidase activity with o-dianisidine and the same Km for H2O2 as the native enzyme.

Target regulated photo induced electron transfer of DNA-Cu nanoparticles and their application for the detection of the hepatitis B gene

2018 ◽  
Vol 10 (22) ◽  
pp. 2614-2622 ◽  
Author(s):  
Qiang Xie ◽  
Dongmin Shi ◽  
Jing Wan ◽  
Xiaojun Zhang ◽  
Guangfeng Wang
Keyword(s):  
Electron Transfer ◽  
Hepatitis B ◽  
Copper Nanoparticles ◽  
Fluorescent Probes ◽  
Cu Nanoparticles ◽  
Photo Induced Electron Transfer ◽  
Fluorescence Quencher ◽  
Dna Template ◽  
Distinct Features

Despite the distinct features of polythymine (T)-templated copper nanoparticles (polyT-Cu NPs) as fluorescent probes for various biosensors, most of the reported methods involve labeling with an appropriate fluorescence quencher, or the addition of enzyme to digest the DNA-template.

scholarly journals A DyP-Type Peroxidase of Pleurotus sapidus with Alkene Cleaving Activity

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1536
Author(s):  
Nina-Katharina Krahe ◽  
Ralf G. Berger ◽  
Franziska Ersoy
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Peroxidase Activity ◽  
Tertiary Structure ◽  
Sulphonic Acid ◽  
Anthraquinone Dyes ◽  
Cleavage Activity ◽  
Pleurotus Sapidus ◽  
Β Carotene

Alkene cleavage is a possibility to generate aldehydes with olfactory properties for the fragrance and flavor industry. A dye-decolorizing peroxidase (DyP) of the basidiomycete Pleurotus sapidus (PsaPOX) cleaved the aryl alkene trans-anethole. The PsaPOX was semi-purified from the mycelium via FPLC, and the corresponding gene was identified. The amino acid sequence as well as the predicted tertiary structure showed typical characteristics of DyPs as well as a non-canonical Mn2+-oxidation site on its surface. The gene was expressed in Komagataella pfaffii GS115 yielding activities up to 142 U/L using 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) as substrate. PsaPOX exhibited optima at pH 3.5 and 40 °C and showed highest peroxidase activity in the presence of 100 µM H2O2 and 25 mM Mn2+. PsaPOX lacked the typical activity of DyPs towards anthraquinone dyes, but oxidized Mn2+ to Mn3+. In addition, bleaching of β-carotene and annatto was observed. Biotransformation experiments verified the alkene cleavage activity towards the aryl alkenes (E)-methyl isoeugenol, α-methylstyrene, and trans-anethole, which was increased almost twofold in the presence of Mn2+. The resultant aldehydes are olfactants used in the fragrance and flavor industry. PsaPOX is the first described DyP with alkene cleavage activity towards aryl alkenes and showed potential as biocatalyst for flavor production.

Preparation of porphyrin modified CO9S8 nanocomposites and application for colorimetric biosensing of H2O2

2018 ◽  
Vol 22 (09n10) ◽  
pp. 935-943 ◽  
Author(s):  
Yan Gao ◽  
Chunqiao Jin ◽  
Miaomiao Chen ◽  
Xixi Zhu ◽  
Min Fu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Peroxidase Activity ◽  
Catalytic Mechanism ◽  
Color Change ◽  
Colorimetric Detection ◽  
Buffer Solution ◽  
Hydrogen Peroxide Detection ◽  
Steady State Kinetics ◽  
One Step

Hydrogen peroxide detection has been widely applied in the fields of biology, medicine, and chemistry. Colorimetric detection of hydrogen peroxide has proven to be a fast and convenient method. In this work, 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin modified Co[Formula: see text]S[Formula: see text] nanocomposites (H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] were prepared via a facile one-step hydrothermal method. H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] nanocomposites were demonstrated to possess an enhanced mimetic peroxidase activity toward the substrate, 3,3[Formula: see text],5,5[Formula: see text]-tetramethylbenzidine (TMB), which can be oxidized to oxTMB (oxidized TMB) in a buffer solution of hydrogen peroxide with a color change from colorless to blue. The catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] was further analyzed by steady-state kinetics, and H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] had high affinity towards both TMB and H[Formula: see text]O[Formula: see text]. Furthermore, fluorescence and ESR data revealed that the catalytic mechanism of the peroxidase activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] is due to hydroxyl radicals generated from decomposition of H[Formula: see text]O[Formula: see text]. Based on the catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text], a sensitive colorimetric sensor of H[Formula: see text]O[Formula: see text] with a detection limit of 6.803 [Formula: see text]M as well as a range of 7–100 [Formula: see text]M was designed.

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