title: Degradation of plasma bilirubin by a bilirubin oxidase derivative which has a relatively long half-life in the circulation.
abstract: To enhance degradation of unconjugated bilirubin in hyperbilirubinemic subjects, we synthesized a bilirubin oxidase (EC 1.3.3.5) (BO) derivative (PEGBO) by covalently linking (2,4-bis[O-methoxy(polyethyleneglycol)]-6-chloro-s-triazine) (PEG) to the enzyme. Intravenously injected BO in rats disappeared from the circulation with a half-life of 2.5 min; the half-life of PEGBO was 190 min. Intravenously injected BO minimally and transiently decreased plasma bilirubin levels in jaundiced Gunn rats and in bile-duct-ligated jaundiced rats. In contrast, PEGBO rapidly and substantially decreased plasma bilirubin levels and the effect persisted for longer than 3 h. Renal dysfunction often occurs in patients with liver diseases. To study the role of bilirubin toxicity for the kidney, functions of transtubular transport for organic anions was measured in bile-duct-ligated jaundiced animals before and after treatment with PEGBO. Bile duct ligation decreased urinary excretion of phenolsulfophthalein (PSP), an organic anion used for renal function test. Treatment of the jaundiced animals with PEGBO increased the rate of PSP disappearance from the circulation and normalized its urinary excretion. Thus, PEGBO might be useful for the study of bilirubin toxicity in jaundiced animals.
authors.affiliation: Department of Biochemistry, Kumamoto University Medical School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sugi
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Morino
mesh_terms: D000818:Animals; D001652:Bile Ducts; D001663:Bilirubin / Q000097:blood*; D006207:Half-Life; D006932:Hyperbilirubinemia / Q000188:drug therapy; D005779:Immunodiffusion; D007668:Kidney / Q000187:drug effects; D008026:Ligation; D008099:Liver / Q000378:metabolism; D010088:Oxidoreductases / Q000097:blood / Q000276:immunology; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011092:Polyethylene Glycols / Q000097:blood* / Q000138:chemical synthesis / Q000276:immunology / Q000494:pharmacology; D051381:Rats; D011911:Rats, Gunn; D014227:Triazines / Q000097:blood* / Q000138:chemical synthesis / Q000276:immunology / Q000494:pharmacology
chemical_list: D014227:Triazines; D011092:Polyethylene Glycols; C029761:2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D001663:Bilirubin