Search results for "OXIDASE"

Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase.

2015

This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Δ(1)-pyrroline as degradation product from putrescine indicate that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine, and, to a lesser extent, polyamines, such as spermidine, but not monoamines. The kinetic constants (Km and Vmax) for the two major substrates were 94 ± 10 μM and 2.3 ± 0.1 μmol/min·mg for putrescine and 75 ± 5 μM and 0.15 ± 0.02 μmo…

Hydrogen peroxide sensors for cellular imaging based on horse radish peroxidase reconstituted on polymer-functionalized TiO2 nanorods

2011

We describe the reconstitution of apo-horse radish peroxidase (apo-HRP) onto TiO2 nanorods functionalized with a multifunctional polymer. After functionalization, the horse radish peroxidase (HRP) functionalized TiO2 nanorods were well dispersible in aqueous solution, catalytically active and biocompatible, and they could be used to quantify and image H2O2 which is a harmful secondary product of cellular metabolism. The shape, size and structure of TiO2 nanorods (anatase) were analyzed by transmission electron microscopy (TEM), high resolution TEM (HRTEM), electron diffraction (ED) and X-ray diffraction (XRD). The surface functionalization, HRP reconstitution and catalytic activity were con…

The mechanism of the antioxidant effect of smoked paprika from La Vera, Spain

2013

This study aimed at further investigating the antioxidant effect of smoked paprika (Pimenton La Vera, Spain) in healthy subjects. Crossover study included male students (age 20.6 ± 1.7 years) who consumed smoked or non-smoked paprika (2 g/day, 20 times, over 30 days). After ingestion of smoked paprika, plasma malondialdehyde (MDA) levels were significantly (p < 0.01) reduced versus basal and non-smoked paprika ingestion values. Reduced glutathione (GSH) levels were increased and oxidised glutathione (GSSG) levels reduced significantly (p < 0.05) in paired subjects after consumption of smoked paprika. Smoked paprika significantly increased mRNA levels of glutathione peroxidase and cytochrome…

Antioxidant enzymes in lymphocites from essential hypertension patients

2002

Inactivation and Regeneration Kinetics of Horseradish Peroxidase Heated at High Temperatures.

1997

The inactivation kinetics of horseradish peroxidase (HRP) heated in capillary tubes in the range 110 to 135°C was studied. Its regeneration kinetics when stored at 4 and 25°C was also considered. As the severity of the treatment increased, the absolute value of the regeneration decreased. The storage temperature of the enzyme did not affect the percentage of maximum activity regenerable, although when this temperature was raised from 4 to 25°C the speed of regeneration increased. Kinetics of HRP inactivation determined after heating and after regeneration were compared. Both forms of the enzyme showed similar behavior with first-order inactivation kinetics, with Ea = 19.5 ± 1.0 kcal/mol and…

Thermal inactivation at high temperatures and regeneration of green asparagus peroxidase

2019

A spectrophotometric method was developed for determining the peroxidase activity of green asparagus in small samples. The optimum conditions for the analysis in the cuvette were 45 mM of H2O2 36 mM of guaiacol, and pH 7. The method can be used to determine enzyme activity at up to two decimal reductions. A study was performed of the regeneration and inactivation kinetics of the enzyme when heated between 90 and 125°C. Regenerated asparagus peroxidase reached its maximum activity after being stored 6 days at 25°C. The regenerated enzyme followed first-order inactivation kinetics, showing an Ea = 13.62 kcal/mol and k100°C = 2.07 min-1.

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography

1987

Abstract The reversed-phase chromatography of proteins by gradient elution with acidic, low-ionic-strength aqueous—organic eluents is often associated with losses of the biological activity of the protein. In this study, the enzymatic activities of catalase, horseradish peroxidase and pepsin were examined under static and dynamic column conditions on non-porous, monodisperse 1.5-μm reversed-phase silicas with various n -alkyl ligands. Catalase readily lost its enzymatic activity under the influence of the acidic aqueous—organic eluents in the absence of the reversed-phase packing, whereas peroxidase was partially deactivated as a result of combined mobile phase and stationary phase effects …

Selenium supplementation improves antioxidant capacity in vitro and in vivo in patients with coronary artery disease

2008

Background Selenium is a central determinant of antioxidative glutathione peroxidase 1 (GPx-1) expression and activity. The relevance of selenium supplementation on GPx-1 in coronary artery disease (CAD) needs to be established. We assessed the effect of selenium supplementation on GPx-1 in cell culture and on endothelial function in a prospective clinical trial. Methods Human coronary artery endothelial cells were incubated with 5.78 to 578 nmol/L sodium selenite, Se-methyl-selenocysteine hydrochloride, or seleno-l-methionine. Glutathione peroxidase 1 mRNA and protein expression and activity were measured. Coronary artery disease patients (n = 465) with impaired endothelial function (flow-…

Biochemical characterization of two functional human liver acyl-CoA oxidase isoforms 1a and 1b encoded by a single gene

2007

Abstract Human acyl-CoA oxidase 1 (ACOX1) is a rate-limiting enzyme in peroxisomal fatty acids β-oxidation and its deficiency is associated with a lethal, autosomal recessive disease, called pseudoneonatal-adrenoleukodystrophy. Two mRNA variants, transcribed from a single gene encode ACOX1a or ACOX1b isoforms, respectively. Recently, a mutation in a splice site has been reported [H. Rosewich, H.R. Waterham, R.J. Wanders, S. Ferdinandusse, M. Henneke, D. Hunneman, J. Gartner, Pitfall in metabolic screening in a patient with fatal peroxisomal β-oxidation defect, Neuropediatrics 37 (2006) 95–98.], which results in the defective peroxisomal fatty acids β-oxidation. Here, we show that these mRNA…

Determination of Plasma Lipid Hydroperoxides by an NADPH/NADP + Coupled Enzyme Reaction System. Evaluation of a Method

1998

Summary: Several techniques based on different principles have been proposed to measure lipid hydroperoxides. Enzymatic methods are sensitive and can be quite specific but they are subject to interference by inhibitors and not all are stoichiometric. The present work proposes some modifications of the Heath & Tappel (Anal Biochem 1976; 7:184—91) enzymatic method of determination of lipid hydroperoxides in order to standardize and automate it and to meet the analytical criteria required for a biological assay. The proposed new protocol and the automated assay give acceptable within-run and between-run precisions, with coefficients of variation of 3.34% and 5.80%, respectively, at the usual p…