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Abstract  

Kinetics and concentration profile associated with the regulated radiodegradation of bilirubin in an organic solvent were assessed. The pure unconjugated specimen was prepared in chloroform (40.0 µM). The depletion of bilirubin was almost linear with dose, and complete degradation was accomplished with doses in excess of 100 Gy. The method was also evaluated for the explicit production of the long-wavelength isomer of biliverdin, which was characterized spectrometrically by an absorbance band in the region 600–650 nm. Results including differences in air, N2 and O2 purged samples are presented to identify the atmospheric medium for optimum production of biliverdin. The process was regulated by controlling the dose. The general rate constant of the depletion process was estimated at a dose rate of 5.67·10−2Gy·s−1. The method is a convenient substitute for light illumination studies of bilirubin.

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Abstract  

Biliverdin is a useful component in various aspects of biochemistry and biosynthesis, but its synthetic preparation is often long-winded. Micro-production (and subsequent isolation) by solar photolysis and gamma radiolysis of bilirubin provides rapid in vitro generation. Both methods are competitive, and this article discusses their merits and limitations for application in biosynthetic research. The investigation assumed a comparative study to evaluate the relative potential of the photolytic and radiolytic phenomena in this respect. The calculated rate of incident energy in the case of solar photolysis was roughly30.4.10-2 W, and about 5.70.10-4 W during gamma-irradiation (from a 137Cs source). In both cases the bilirubin (40 µM) degradation was pronounced in the initial few minutes of exposure, producing respective depletion rates of approximately 6.8 µM/min and 2.4 µM/min. Overall, both applications showed declining bilirubin concentrations close to 90%, after about 30 minutes. However, the corresponding production of biliverdin was higher by about 50% in the photolytic application. To account for heat-up effects in the photolytic application, thermal effects were studied up to 65 °C, and it was found that, as a result of this, a reduction in bilirubin concentration of about 40% was encountered. The species of interest were monitored spectrophotometrically, and the composite results showed that regulated production of biliverdin is possible under certain conditions.

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Fulchuk KH, Contin JM, Dzedzic TS, Feng Z, French TC, Heffron GJ, et al.: A role for biliverdin IXa in dorsal axis development of Xenopus laevis embryos. Proc. Natl. Acad. Sci. USA. 99, 251–256 (2002) Heffron G

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to iron and porphyrin IXa and porphyrin IX to biliverdin by hem oxygenase. The green coloured biliverdin is then reduced to yellow coloured bilirubin by biliverdin reductase [ 3–5 ] ( Fig. 1 ). The bilirubin molecule thus formed consists of a

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. Wegiel B , Otterbein LE : Go green: the anti-inflammatory effects of biliverdin reductase . Front Pharmacol 3 , 47 ( 2012 ) 39. Fowler

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Stocker, R., Peterhans, E.: Antioxidant properties of conjugated bilirubin and biliverdin biologically relevant scavenging of hypochlorous acid. Free Rad. Res. Com., 1989, 6 , 57–66. Peterhans E

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a ubiquitous microsomal rate-limiting enzyme involved in the oxidative degradation of heme to biliverdin (BV), which is rapidly converted into bilirubin (BR) by BV reductase. During this step, iron is released from the heme ring and carbon monoxide

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experiment conducted with an animal model, it was shown that HMOX1 stimulated insulin products and reduced IR. It was also reported that biliverdin reductase has multiple functions affecting cell signaling and modulating immune system response [ 16

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