The oxidation of heme to biliverdin IXalpha by heme oxygenase involves regiospecific alpha-meso-hydroxylation followed by extrusion of the alpha-meso-carbon as CO. In an earlier study, enzymatic oxidation of the four meso-methylmesoheme isomers suggested that the reaction regiospecificity is sensitive to the electronic properties of the meso-methyl group (Torpey, J. W., and Ortiz de Montellano,...

We have previously suggested that an inherent defect in hepatic haem utilization was responsible for the rapid stimulation of hepatic microsomal haem oxygenase activity observed in selenium-deficient rats given phenobarbital, a well known inducer of haem formation. To test this hypothesis, hepatic haem content was deliberately raised in selenium-deficient rats by administration of either trypto...

Radiotherapy Sensitization Enhancing the cellular radiosensitivity is instrumental for improving efficacy of tumor radiotherapy. In article number 2206415, Junping Wang, Cheng and co-workers report a tumor-penetrating nanomaterial iCoDMSN constituted with dendritic mesoporous silica nanoparticles iRGD peptide-conjugated [email protected] nanodots. By decreasing KEAP1 expression upregulating nuc...

The heat shock protein heme oxygenase-1 (HO-1) is regulated by a variety of physiological and pharmacological factors. In skeletal muscle tissue, HO-1 has been shown to be induced only by exercise and electrical stimulation in vivo. Both hemin and sodium nitroprusside (SNP) are potent inducers of HO-1 in other tissues. In this study, we examined the effects of these two agents on HO-1 induction...

Recent findings that heme oxygenase-1 can be induced by oxidative stress and inflammation in many different cellular systems, and that carbon monoxide (CO) produced as a by-product of this enzyme is a signaling molecule, have generated a major research area with hundreds of studies published over the last few years. The measurement of expired CO concentration has been used in humans as a biomar...

The synthetic metalloporphyrin, Cr-protoporphyrin, as a potent competitive inhibitor of heme oxygenase activity in rat spleen, liver, and kidney. When administered to neonatal animals in a single dose immediately after birth, Cr-protoporphyrin suppresses postnatal hyperbilirubinemia and produces a marked and sustained lowering of heme oxidation activity in liver, spleen, and kidney. The metallo...