Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1An improved method for purifying hexose oxidase (D-hexose: O(2) 1-oxidoreductase, EC 1.1.3.5) from the marine red alga Chondrus crispus is described for obtaining enzyme suitable for structural characterization and use in bioconversion of lactose to lactobionic acid. This involved extracting enzyme from finely ground lyophilized tissue in sodium phosphate buffer (pH 7) containing 20% ammonium sulfate, eliminating the previously used solvent extraction and protease treatments, and by applying Poros perfusion chromatography media to achieve rapid separations of high resolution. Primary separation of contaminating phycobiliproteins and carrageenans was achieved using Poros DEAE-50. Sequential HPLC purification steps using Poros HP2 and Poros HQ were followed by Sephacryl S200 h chromatography. Enzyme activity was determined with a peroxidase-coupled assay using 2,2'-azino-bis (3-ethylbenzthiazoline-6 sulfonic acid) substrate. A final specific activity of 69 U/mg was obtained, representing a 100-fold purification with an activity recovery of about 10%. A native size of approximately 117,000 Da was determined by size exclusion chromatography, and SDS-PAGE revealed the presence of 38,000 and 29,000 Da polypeptides that appear to be derived from a 65,000 Da subunit. Further properties of the enzyme are described.
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PMID:Hexose oxidase from Chondrus crispus: improved purification using perfusion chromatography(*). 1142 34

A commercial glucose oxidase (GOX) from Aspergillus niger was partially characterized. The enzyme exhibited a two-step transfer mechanism, and the kinetic constants toward glucose and oxygen were determined. Under conditions similar to dough making (glucose concentration and pH), GOX does not exhibit maximum activity. A hexose oxidase (HOX) from Chondrus crispus was partially characterized as well. The HOX activity is not far from the optimum in the kneading conditions (pH and glucose concentration). A peroxidase (POD) purified from wheat germ was used to oxidize ferulic acid in the presence of GOX or HOX. Hydrogen peroxide produced during the glucose oxidation activates the wheat germ POD. Ferulic acid oxidation in solutions containing different ratios of POD + GOX or HOX + POD was followed by UV spectrophotometry. For the same dosage, the HOX-POD system is the most efficient for peroxidase activation. Using absorbance data and kinetic constants of GOX and POD, a mathematical model describing the release or consumption of the different reactants (hydrogen peroxide, oxygen, and ferulic acid) in the medium was developed, and experimental data correlated well with calculated values. The results obtained will be applied to investigate the effect of GOX and HOX activities on the rheological properties of dough.
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PMID:Analysis and modeling of the ferulic acid oxidation by a glucose oxidase-peroxidase association. Comparison with a hexose oxidase-peroxidase association. 1518 21