The enzymatic and chemical reduction of extended biliverdins.
The substrate specificity of rat liver biliverdin reductase was probed using helical and extended biliverdins. The former were the ZZZ-all-syn biliverdins IX alpha and IX gamma, and the latter were the 5Z-syn, 10Z-syn, 15Z-anti; 5Z-anti, 10E-anti, 15E-anti biliverdins. It was found that the reduction rates of the biliverdins increased with the progressive stretching of their conformations. The most extended biliverdin was reduced at a higher rate than biliverdin IX alpha. The chemical reduction rates to bilirubins followed a similar pattern. Nucleophilic addition of 2-mercaptoethanol to the C10 methine was also favored in the extended biliverdins.
Frydman
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Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Bari
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Tomaro
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ML
Frydman
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B
D000818:Animals; D001663:Bilirubin / Q000031:analogs & derivatives*; D001664:Biliverdine / Q000031:analogs & derivatives / Q000378:metabolism*; D001894:Borohydrides; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008623:Mercaptoethanol; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D051381:Rats; D013056:Spectrophotometry, Ultraviolet; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D001894:Borohydrides; D008623:Mercaptoethanol; C025364:sodium borohydride; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C019789:biliverdin reductase; D001664:Biliverdine; D001663:Bilirubin