title: Polyethylene glycol derivative-modified cholesterol oxidase soluble and active in benzene.
abstract: Cholesterol oxidase from Nocardia sp. was modified with a synthetic copolymer of polyoxyethylene allylmethyldiether (PEG) and maleic acid anhydride (MA anhydride), poly(PEG-MA anhydride). The modified cholesterol oxidase, in which 64% of the amino groups in the protein molecule were coupled to poly(PEG-MA), was soluble in organic solvents and catalyzed the oxidation reaction of cholesterol in benzene to form 4-cholesten-3-one with the enzymic activity of 0.6 mumol/min/mg protein. Using the modified cholesterol oxidase together with polyethylene glycol-modified peroxidase, coupled reactions shown below took place in Cholesterol + O2----4-Cholesten-3-one + H2O2 H2O2 + o-Phenylenediamine----H2O + Oxidized o-Phenylenediamine transparent benzene solution, not in an emulsified system. The oxidation of cholesterol was directly determined in benzene by measuring the absorbance of oxidized o-phenylenediamine at 490 nm.
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D001554:Benzene; D002789:Cholesterol Oxidase / Q000378:metabolism*; D005663:Furans / Q000494:pharmacology*; D007700:Kinetics; D008299:Maleic Anhydrides / Q000138:chemical synthesis / Q000494:pharmacology*; D009615:Nocardia / Q000201:enzymology*; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000494:pharmacology*; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D005663:Furans; D008299:Maleic Anhydrides; C054144:polyoxyethylene allylmethyl diether-maleic anhydride copolymer; D011092:Polyethylene Glycols; D015096:3-Hydroxysteroid Dehydrogenases; D002789:Cholesterol Oxidase; D001554:Benzene