The reaction mixture prepared for the measurement of HO activity contained the following compounds in a final volume of 1.5 mL: 2 mM glucose 6-phosphate, 0.14 U/mL glucose-6-phosphate dehydrogenase, 15 [micro]M heme, 150 [micro]M [beta]-NADPH, 120 [micro]g/mL rat liver cytosol as a source of
biliverdin reductase, 2 mM Mg[Cl.sub.2], 100 mM potassium phosphate buffer and 150 [micro]L of the supernatant.
"In addition to having the highest concentration of
biliverdin recorded for any animal, these lizards have somehow evolved a resistance to bile pigment toxicity," lead author Zachary Rodriguez from Louisiana State University said in a (https://www.eurekalert.org/pub_releases/2018-05/lsu-tmo051018.php) statement .
In addition, GSH depletion induces heme oxygenase-1 (HO-1), a key microsomal enzyme in heme degradation to carbon monoxide (CO), iron ([Fe.sup.2+]), and
biliverdin; this latter being converted into bilirubin by the cytosolic
biliverdin reductase [53, 54].
Third, HO-1 catalyzes the oxidation of heme to generate CO and
biliverdin. These products have anti-inflammatory, antioxidant, antiapoptotic, and antithrombotic properties [1].
This signaling hypothesis relies on the assumption that
biliverdin, the pigment responsible for blue-green eggshell coloration, is an indicator of female quality.
The cytoprotective effects of bilirubin and
biliverdin on rat hepatocytes and human erythrocytes and the impact of albumin.
The skeleton has been reported to contain the blue pigment,
biliverdin IX[alpha], which is formed by heme oxygenase (HO) during heme decomposition.
Heme-HO system metabolizes heme to equimolar concentrations of
biliverdin (BV), carbon monoxide (CO), and iron.
In partial agreement with these data, it was recently found that
Biliverdin reductase A protects against hepatic steatosis by inhibiting glycogen synthase kinase 3[beta] (GSK3[beta]) by enhancing serine 9 phosphorylation, which inhibits its activity: in particular, GSK3[beta] phosphorylates serine 73 of the PPAR[alpha], which in turn increased ubiquitination and protein turnover, as well as decreasing activity [39].
Heme oxygenase-1 (HO-1), an antioxidant and cytoprotective enzyme [23], is one of members of the heme oxygenase family [24, 25], which equimolarly decompose heme to
biliverdin, free iron, and carbon monoxide (CO).
Heme oxygenase-1 (HO-1), an inducible and rate-limiting enzyme, appears to catalyze the degradation of heme to carbon monoxide and
biliverdin, which is subsequently converted to bilirubin (a powerful antioxidant) by
biliverdin reductase [61].
This process produces
biliverdin and carbon monoxide, which can ameliorate oxidative stress-mediated neurodegenerative disorders [34, 35].
