Search results for "OXIDASE"
showing 10 items of 927 documents
The presence of conifer resin decreases the use of the immune system in wood ants.
2008
5 pages; International audience; 1. Wood ants ( Formica paralugubris ) incorporate large amounts of solidified conifer resin into their nest, which reduces the density of many bacteria and fungi and protects the ants against some detrimental micro-organisms. By inducing an environment unfavourable to pathogens, the presence of resin may allow workers to reduce the use of their immune system. 2. The present study tested the hypothesis that the presence of resin decreases the immune activity of wood ants. Specifically, three components of the humoral immune defences of workers kept in resin-rich and resin-free experimental nests (antibacterial, lytic, and prophenoloxidase activities) were com…
The noncovalent dimerization of a G-quadruplex/hemin DNAzyme improves its biocatalytic properties.
2020
While many protein enzymes exert their functions through multimerization, which improves both selectivity and activity, this has not yet been demonstrated for other naturally occurring catalysts. Here, we report a multimerization effect applied to catalytic DNAs (or DNAzymes) and demonstrate that the enzymatic efficiency of G-quadruplexes (GQs) in interaction with the hemin cofactor is remarkably enhanced by homodimerization. The resulting non-covalent dimeric GQ–DNAzyme system provides hemin with a structurally defined active site in which both the cofactor (hemin) and the oxidant (H2O2) are activated. This new biocatalytic system efficiently performs peroxidase- and peroxygenase-type biot…
New molecular aspects of regulation of mitochondrial activity by fenofibrate and fasting
2000
Abstract Fenofibrate and fasting are known to regulate several genes involved in lipid metabolism in a similar way. In this study measuring several mitochondrial enzyme activities, we demonstrate that, in contrast to citrate synthase and complex II, cytochrome c oxidase (COX) is a specific target of these two treatments. In mouse liver organelles, Western blot experiments indicated that mitochondrial levels of p43, a mitochondrial T3 receptor, and mitochondrial peroxisome proliferator activated receptor (mt-PPAR), previously described as a dimeric partner of p43 in the organelle, are increased by both fenofibrate and fasting. In addition, in PPARα-deficient mice, this influence was abolishe…
Regulation of the synthesis of aryl metabolites by phospholipid sources in the white-rot fungus Bjerkandera adusta
1999
The white-rot basidiomycete Bjerkandera adusta was cultivated in a liquid medium enriched with l-phenylalanine and various phospholipid sources (lecithin, egg yolk and asolectin). Three aromatic metabolites (benzaldehyde, benzyl alcohol and benzoic acid) were produced under these culture conditions. High concentrations of benzaldehyde (404 mg l–1) were obtained when the cultures were supplemented with 10 g lecithin l–1. Benzyl alcohol production was promoted when the strain was grown with 5 or 10 g lecithin l–1. In the absence of or with a low concentration of lecithin (2.5 g l–1), benzoic acid was the major aryl metabolite synthesized. The results presented here indicate that aryl alcohol …
Rational backbone redesign of a fructosyl peptide oxidase to widen its active site access tunnel
2020
Fructosyl peptide oxidases (FPOXs) are enzymes currently used in enzymatic assays to measure the concentration of glycated hemoglobin and albumin in blood samples, which serve as biomarkers of diabetes. However, since FPOX are unable to work directly on glycated proteins, current enzymatic assays are based on a preliminary proteolytic digestion of the target proteins. Herein, to improve the speed and costs of the enzymatic assays for diabetes testing, we applied a rational design approach to engineer a novel enzyme with a wider access tunnel to the catalytic site, using a combination of Rosetta design and molecular dynamics simulations. Our final design, L3_35A, shows a significantly wider …
Potential anticarcinogenic peptides from bovine milk.
2012
Bovine milk possesses a protein system constituted by two major families of proteins: caseins (insoluble) and whey proteins (soluble). Caseins (αS1,αS2,β, andκ) are the predominant phosphoproteins in the milk of ruminants, accounting for about 80% of total protein, while the whey proteins, representing approximately 20% of milk protein fraction, includeβ-lactoglobulin,α-lactalbumin, immunoglobulins, bovine serum albumin, bovine lactoferrin, and lactoperoxidase, together with other minor components. Different bioactivities have been associated with these proteins. In many cases, caseins and whey proteins act as precursors of bioactive peptides that are released, in the body, by enzymatic pro…
ISOLATION OF CYTOCHROME OXIDASE COMPLEX FROM SEA URCHIN MITOCHONDRIAL INNER MEMBRANES
1996
Cytochrome oxidase complex has been isolated and purified from sea urchin mitochondrial inner membranes. The complex exhibited a discrete number of bands in PAGE and a 17 kDa band was recognized by an anti-human subunit IV antibody. No bands were recognized by an anti-yeast hsp60 antibody and an anti-sea urchin β ATPase subunit.
An update of the known distribution and status of Cherax spp. in Italy (Crustacea, Parastacidae)
2022
To date, only two Cherax species have been reported to occur in Italy, i.e., C. destructor Clark, 1936 and C. quadricarinatus (von Martens, 1868), both in the wild and in aquaculture farms. Therefore, we aimed to update their current status and distribution in Italian mainland and Sicily. In addition, we investigated the origin of their known populations, and their possible routes of invasion. In order to genetically characterize the Cherax populations occurring in Italian inland waters and aquaculture facilities, the barcode region of the mtDNA gene cytochrome oxidase subunit I was sequenced in the available specimens originating from an aquaculture facility and a museum collection. The sa…
The ascidian prophenoloxidase activating system
2009
Phenoloxidases/tyrosinases initiate melanin synthesis in almost all organisms, and are involved in different biological activities such as the colour change of human hair and the browning or blackening of fruit skin etc. In many invertebrates, defence reactions are linked to phenoloxidase activity and/or melanization. Contacts with foreign molecules are able to trigger the prophenoloxidase (proPO) system that requires serine protease cleavage for activating the zymogen to phenoloxidase (PO). It is generally accepted that the proPO system is fully expressed in arthropods, and, recently, progress in the regulation of crustacean and insect proPO activation steps have been achieved. After cells…
Harnessing nature's insights: synthetic small molecules with peroxidase-mimicking DNAzyme properties.
2011
International audience