Natural cyclic tetrapyrroles feature outstanding capacity for binding transition metal ions, furnishing Nature with the important metallo-porphyrinoid 'Pigments of Life', such as heme, chlorophyll (Chl) and vitamin B12. In contrast, linear tetrapyrroles are not generally ascribed a biologically relevant ability for metal-binding. Indeed, when heme or Chl are degraded to natural linear tetrapyrr...

BACKGROUND Hyperhomocysteinemia (HHcy) is an independent risk factor for liver diseases, such as fatty liver and hepatic fibrosis. However, the mechanisms underlying this pro-oxidative effect of homocysteine (Hcy) in hepatocytes remain largely unknown. Thus, we investigated the effect of Hcy on the gene expression of heme oxygenase-1 (HO-1), the primary rate-limiting enzyme in heme catabolism a...

Within the globin superfamily, protoglobins (Pgb) belong phylogenetically to the same cluster of two-domain globin-coupled sensors and single-domain sensor globins. Multiple functional roles have been postulated for Methanosarcina acetivorans Pgb (Ma-Pgb), since the detoxification of reactive nitrogen and oxygen species might co-exist with enzymatic activity(ies) to facilitate the conversion of...

STUDY OBJECTIVE We evaluate the effectiveness and safety of emergency medical services (EMS) provider use of a checklist to triage alcohol-inebriated patients directly to a detoxification facility, rather than an emergency department (ED). METHODS A retrospective cohort study was conducted of all patients evaluated during a 2-year period, from 2003 to 2005, by EMS providers who used a detoxif...

Heme oxygenase-1 is a microsomal enzyme that, when induced by stress, protects the cells from oxidative injury. Heme oxygenase-1 participates in the cleavage of the heme ring producing biliverdin, CO and ferrous Fe. The released Fe becomes part of intracellular Fe pool and can be stored in ferritin or released by an iron exporter. The mechanism by which heme enters cells is not completely under...

Alcohol Health & Research World lcohol detoxification can be defined as a period of medical treatment, usually including counseling, during which a person is helped to overcome physical and psychological dependence on alcohol (Chang and Kosten 1997). The immediate objectives of alcohol detoxification are to help the patient achieve a substancefree state, relieve the immediate symptoms of withdr...

Heme plays key regulatory roles in numerous molecular and cellular processes for systems that sense or use oxygen. In the yeast Saccharomyces cerevisiae, oxygen sensing and heme signaling are mediated by heme activator protein 1 (Hap1). Hap1 contains seven heme-responsive motifs (HRMs): six are clustered in the heme domain, and a seventh is near the activation domain. To determine the functiona...

Heme is a cofactor in proteins that function in almost all sub-cellular compartments and in many diverse biological processes. Heme is produced by a conserved biosynthetic pathway that is highly regulated to prevent the accumulation of heme--a cytotoxic, hydrophobic tetrapyrrole. Caenorhabditis elegans and related parasitic nematodes do not synthesize heme, but instead require environmental hem...

Human pathogen group A streptococcus (GAS) can take up heme from host heme-containing proteins as a source of iron. Little is known about the heme acquisition mechanism in GAS. We recently identified a streptococcal cell surface protein (designated Shp) and the lipoprotein component (designated HtsA) of an ATP-binding cassette (ABC) transporter made by GAS as heme-binding proteins. In an effort...

Heme is an essential molecule expressed ubiquitously all through our tissues. Heme plays major functions in cellular physiology and metabolism as the prosthetic group of diverse proteins. Once released from cells and from hemeproteins free heme causes oxidative damage and inflammation, thus acting as a prototypic damage-associated molecular pattern. In this context, free heme is a critical comp...