The Oxidation of Phenylhydrazine by Tyrosinase

Sung, Yi Ming; Gayam, Srivardhan Reddy; Wu, Shu-Pao

doi:10.1007/s12010-013-0165-7

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…It has previously been described as both an inhibitor and substrate for a tyrosinase [48], ultimately resulting in an o -quinone. Our reaction with laccases produced a similar UV-VIS spectrum, indicating that the same reaction occurs, and both laccases were found to oxidize this compound.…”

Section: Resultsmentioning

confidence: 99%

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

2014

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The limitations of fungal laccases at higher pH and salt concentrations have intensified the search for new extremophilic bacterial laccases. We report the cloning, expression, and characterization of the bacterial cotA from Bacillus clausii, a supposed alkalophilic ortholog of cotA from B. subtilis. Both laccases were expressed in E. coli strain BL21(DE3) and characterized fully in parallel for strict benchmarking. We report activity on ABTS, SGZ, DMP, caffeic acid, promazine, phenyl hydrazine, tannic acid, and bilirubin at variable pH. Whereas ABTS, promazine, and phenyl hydrazine activities vs. pH were similar, the activity of B. clausii cotA was shifted upwards by ∼0.5–2 pH units for the simple phenolic substrates DMP, SGZ, and caffeic acid. This shift is not due to substrate affinity (KM) but to pH dependence of catalytic turnover: The kcat of B. clausii cotA was 1 s−1 at pH 6 and 5 s−1 at pH 8 in contrast to 6 s−1 at pH 6 and 2 s−1 at pH 8 for of B. subtilis cotA. Overall, kcat/KM was 10-fold higher for B. subtilis cotA at pHopt. While both proteins were heat activated, activation increased with pH and was larger in cotA from B. clausii. NaCl inhibited activity at acidic pH, but not up to 500–700 mM NaCl in alkaline pH, a further advantage of the alkali regime in laccase applications. The B. clausii cotA had ∼20 minutes half-life at 80°C, less than the ∼50 minutes at 80°C for cotA from B. subtilis. While cotA from B. subtilis had optimal stability at pH∼8, the cotA from B. clausii displayed higher combined salt- and alkali-resistance. This resistance is possibly caused by two substitutions (S427Q and V110E) that could repel anions to reduce anion-copper interactions at the expense of catalytic proficiency, a trade-off of potential relevance to laccase optimization.

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Section: Resultsmentioning

confidence: 99%

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

2014

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“…Phenylhydrazine (PHZ) proves to be a valuable element in experimental models studying hemolytic anemia due to its toxic effects on RBCs. The auto-oxidation of PHZ generates radicals and reactive oxygen species (ROS), contributing to various adverse responses, including the manifestation of hemolytic anemia [8].…”

Section: Introductionmentioning

confidence: 99%

Antioxidant Properties of Pistacia vera against the Effects of Phenylhydrazine-Induced Hemolytic Anemia on Male Fertility in Mice

Falahati-pour,

Khoradmehr,

Baghery

et al. 2024

Andrologia

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Objective. The reproductive system can be adversely affected by anemia, characterized by elevated free radical production and lipid peroxidation. Conversely, the pistachio is well-known for its antioxidant capabilities. In this study, a mouse model was employed to investigate the safeguarding effects of the aqueous extract of pistachio (Pistacia vera) against oxidative stress induced by phenylhydrazine (PHZ)-triggered hemolytic anemia. Materials and methods. Forty-eight male mice were distributed into six distinct experimental groups (n = 8): control, PHZ, PHZ + 20Pis, PHZ + 80Pis, PHZ + 160Pis, and 80Pis groups. The experimental groups were administered a PHZ dose of 80 mg/kg/48 hr, along with pistachio doses of 20, 80, and 160 mg/kg/day, delivered intraperitoneally. After a period of 35 days, an assessment of sperm count, motility, morphology, and viability was conducted. Additionally, sperm chromatin quality was evaluated through Chromomycin A3, aniline blue, and toluidine blue staining. Hematoxylin–eosin staining was performed to examine the total diameter of seminiferous tubes and spermatogenic cells. Hormonal levels (FSH, LH, T) and antioxidant levels were analyzed using standard kits. Results. The PHZ groups exhibited a noteworthy decrease in various sperm parameters, as well as diminished chromatin quality assays and reduced levels of sex hormones when compared to the control group. Moreover, the morphometric evaluation indicated a substantial reduction in spermatogonia cell number, spermatid count, tubule count, seminiferous diameters, and seminiferous area in the PHZ group. Notably, the Pis group demonstrated the highest concentration of antioxidant contents. Conclusion. The protective impact of P. vera extract against PHZ-induced anemia on the male reproductive system in mice may be attributed to its abundant antioxidant components, which possess therapeutic properties at elevated levels.

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“…10 When PHZ auto-oxi-dizes, reactive oxygen species (ROS) and PHZ-derived radicals are produced, which can result in a range of harmful cellular reactions, including hemolytic anemia. 11 The antioxidant and antianemic properties of ethanol leaf extracts of M. poggei and T. occidentalis were examined in this study in PHZ-induced anemia in Wister albino rats.…”

Section: Introductionmentioning

confidence: 99%

Antioxidant and Anti-Anemic Effects of Ethanol Leaf Extracts of Mucuna poggei and Telfairia occidentalis in Phenyl-Hydrazine-Induced Anemia in Wistar Albino Rats

Udeozor

Ibiam

Uti³

et al. 2022

Ibnosina Journal of Medicine and Biomedical Sciences

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Introduction With the use of recent therapeutic data, several methods for finding medications from untapped natural materials continue to advance research and development. The antioxidant and antianemic effects of ethanol leaf extracts of Telfairia occidentalis and Mucuna poggei in phenylhydrazine-induced anemia in Wister albino rats were investigated. Method A total of 54 male albino rats were randomly assigned to nine experimental groups (n = 6). Anemia was induced in groups 2 to 9 with 10 mg/kg body weight of phenylhydrazine. Group 1 (normal control) rats were administered normal saline only. Group 2 (anemic control) rats were untreated. Group 3 (standard controls) rats were treated with a standard multivitamin, groups 4, 5, and 6 rats were treated with varying doses of M. poggei leaf extract respectively, while groups 7, 8, and 9 rats were treated with similar doses of T. occidentalis leaf extract by oral intubation for 21 days. Results Earlier, the gas chromatography-mass spectrometry analysis indicated eighteen (18) and twenty-nine (29) active compounds present in M. poggei and T. occidentalis, respectively. More so, T. occidentalis and M. poggei were studied for their inhibitory potentials against 2,2-diphenyl-1 picrylhydrazyl-free radicals, nitric oxide, phosphomolybdenum, and ferric-reducing antioxidant power. M. poggei and T. occidentalis also showed the following trend of minerals Mg > Ca > Fe > Na > Zn > Mn > K and Mg > Fe > Ca > Na > K > Mn > Zn, respectively. The results also showed that the packed cell volume, red blood cells, and hemoglobin significantly (p < 0.05) decreased in anemic control rats compared with normal controls and were significantly (p < 0.05) increased on treatment with the leaf extracts. Catalase, superoxide dismutase, glutathione peroxidase activities, and glutathione levels significantly (p < 0.05) decreased in anemic control, compared with normal. However, these significantly (p < 0.05) increased on treatment with the leaf extracts in a dose-independent manner. Malondialdehyde levels took the reverse trend. Conclusion This study indicated that leaf extracts of M. poggei and T. occidentalis can be used in the management of anemia and oxidative stress-related complications

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The Oxidation of Phenylhydrazine by Tyrosinase

Cited by 5 publications

References 28 publications

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

Antioxidant Properties of Pistacia vera against the Effects of Phenylhydrazine-Induced Hemolytic Anemia on Male Fertility in Mice

Antioxidant and Anti-Anemic Effects of Ethanol Leaf Extracts of Mucuna poggei and Telfairia occidentalis in Phenyl-Hydrazine-Induced Anemia in Wistar Albino Rats

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