Hemopexin (HPX) is a plasma protein with the strongest binding capacity to heme and widely involved in modulation of a variety of physiological and pathological processes. The main physiological function of HPX is to bind and transport free toxic heme. Recent studies indicate that HPX also plays roles of anti-oxidant, anti-apoptosis, immune regulation and organic protection. In addition, HPX participates in regulation of cell differentiation and extracellular matrix reconstruction. In recent years, a great deal of progress has been made in studies of the mechanisms of HPX protective effects and on possible clinical application. In the past few years, especially, a number of proteomic studies have demonstrated that HPX could be served as positive molecular biomarkers for cancers of lung, liver, kidney, colon, and uterine myoma as well as osteoarthritis. In this review, recent progress in the biochemical characteristics and function of HPX and its possible clinical applications are summarized.
Heme ; Heme Oxygenase (Decyclizing) ; Hemopexin ; chemistry ; metabolism ; Humans

Catalases are well studied enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. The ubiquity of the enzyme and the availability of substrates made heme catalases the focus of many biochemical and molecular biology studies over 100 years. In human, this has been implicated in various physiological and pathological conditions. Advancement in proteomics revealed many of novel and previously unknown features of this mysterious enzyme, but some functional aspects are yet to be explained. Along with discussion on future research area, this mini-review compile the information available on the structure, function and mechanism of action of human catalase.
Catalase ; chemistry ; metabolism ; physiology ; Heme ; chemistry ; Humans ; Hydrogen Peroxide ; metabolism

OBJECTIVETo investigate the location of heme oxygenase (HO) enzyme in the human testis, and explore the correlation of the expression of HO enzyme with azoospermia by analyzing its different expression levels in the testes of nonobstructive azoospermia, obstructive azoospermia and normal men.

METHODSWe detected the location of the cells expressing HO enzyme in the human testis tissue using immunohistochemistry, determined the mRNA and protein expression levels of HO-1 and HO-2 in the testes of azoospermia patients and normal healthy men by RT-fluorescence quantitative PCR (RT-FQ-PCR) and Western blot, and explored the correlation of HO expressions with the pathogenesis of azoospermia.

RESULTSHO-1 enzyme was expressed mainly in the Sertoli cells and HO-2 enzyme chiefly in the germ cells of the testis tissue. RT-FQ-PCR showed that the expression of HO-1 in the testis tissue was significantly lower in the nonobstructive azoospermia than in the normal and obstructive azoospermia groups (P < 0.05), with no significant difference between the latter two. Western blot revealed no obvious difference between the expression level of HO-1 protein and that of HO-1 mRNA. There were no differences in the expression level of HO-2 protein among the three groups.

CONCLUSIONThe expression level of HO enzyme is significantly decreased in the testis tissue of nonobstructive azoospermia patients, and the expression of HO-1 protein is consistent with that of HO-1 mRNA. As HO-1 protects the testis tissue against various stress injuries through its antioxidant, anti-inflammatory and anti-apoptotic effects, its decreased expression level may be correlated with spermatogenic dysfunction, and therefore considered as a possible mechanism of nonobstructive azoospermia.

Azoospermia ; enzymology ; metabolism ; Case-Control Studies ; Heme Oxygenase (Decyclizing) ; metabolism ; Heme Oxygenase-1 ; metabolism ; Humans ; Male ; Spermatogenesis ; Testis ; enzymology ; metabolism

Cytochrome c is a type of heme proteins that are widely distributed in living organisms. It consists of heme and apocytochrome c, and has potential applications in bioelectronics, biomedicine and pollutant degradation. However, heterologous overexpression of cytochrome c is still challenging. To date, expression of the cytochrome c from uncultured anaerobic methanotrophic archaea has not been reported, and nothing is known about the function of this cytochrome c. A his tagged cytochrome c was successfully expressed in E. coli by introducing a thrombin at the N-terminus of CytC4 and co-expressing CcmABCDEFGH, which is responsible for the maturation of cytochrome c. Shewanella oneidensis, which naturally has enzymes for cytochrome c maturation, was then used as a host to further increase the expression of CytC4. Indeed, a significantly higher expression of CytC4 was achieved in S. oneidensis when compared with in E. coli. The successful heterologous overexpression of CytC4 will facilitate the exploitation of its physiological functions and biotechnological applications.
Anaerobiosis ; Archaea/metabolism* ; Cytochromes c/metabolism* ; Escherichia coli/metabolism* ; Heme/metabolism*

Animals ; Animals, Newborn ; Carbon Monoxide ; metabolism ; Heme Oxygenase (Decyclizing) ; metabolism ; Lung ; metabolism ; Oxygen ; physiology ; Rats

Heme, which exists widely in living organisms, is a porphyrin compound with a variety of physiological functions. Bacillus amyloliquefaciens is an important industrial strain with the characteristics of easy cultivation and strong ability for expression and secretion of proteins. In order to screen the optimal starting strain for heme synthesis, the laboratory preserved strains were screened with and without addition of 5-aminolevulinic acid (ALA). There was no significant difference in the heme production of strains BA, BAΔ6 and BAΔ6ΔsigF. However, upon addition of ALA, the heme titer and specific heme production of strain BAΔ6ΔsigF were the highest, reaching 200.77 μmol/L and 615.70 μmol/(L·g DCW), respectively. Subsequently, the hemX gene (encoding the cytochrome assembly protein HemX) of strain BAΔ6ΔsigF was knocked out to explore its role in heme synthesis. It was found that the fermentation broth of the knockout strain turned red, while the growth was not significantly affected. The highest ALA concentration in flask fermentation reached 82.13 mg/L at 12 h, which was slightly higher than that of the control 75.11 mg/L. When ALA was not added, the heme titer and specific heme production were 1.99 times and 1.45 times that of the control, respectively. After adding ALA, the heme titer and specific heme production were 2.08 times and 1.72 times higher than that of the control, respectively. Real-time quantitative fluorescent PCR showed that the expressions of hemA, hemL, hemB, hemC, hemD, and hemQ genes at transcription level were up-regulated. We demonstrated that deletion of hemX gene can improve the production of heme, which may facilitate future development of heme-producing strain.
Gene Deletion ; Bacillus amyloliquefaciens/metabolism* ; Aminolevulinic Acid/metabolism* ; Heme/metabolism* ; Fermentation

Harmaline and harmine are β-carboline alkaloids with effective pharmacological effects. Harmaline can be transformed into harmine after oral administration. However, enzymes involved in the metabolic pathway remain unclear. In this study, harmaline was incubated with rat liver microsomes (RLM), rat brain microsomes (RBM), blood, plasma, broken blood cells, and heme peroxidases including horseradish peroxidase (HRP), lactoperoxidase (LPO), and myeloperoxidase (MPO). The production of harmine was determined by a validated UPLC-ESI-MS/MS method. Results showed that heme peroxidases catalyzed the oxidative dehydrogenation of harmaline. All the reactions were in accordance with the Hill equation. The reaction was inhibited by ascorbic acid and excess H₂O₂. The transformation of harmaline to harmine was confirmed after incubation with blood, plasma, and broken blood cells, rather than RLM and RBM. Harmaline was incubated with blood, plasma, and broken cells liquid for 3 h, and the formation of harmine became stable. Results indicated an integrated metabolic pathway of harmaline, which will lay foundation for the oxidation reaction of dihydro-β-carboline. Moreover, the metabolic stability of harmaline in blood should not be ignored when the pharmacokinetics study of harmaline is carried out.
Animals ; Harmaline/metabolism* ; Harmine/metabolism* ; Heme ; Hydrogen Peroxide ; Rats ; Tandem Mass Spectrometry

Heme/metabolism* ; Cryoelectron Microscopy ; Membrane Transport Proteins ; Escherichia coli Proteins/metabolism*

This study investigated the expression of hemeoxygenase-1 (HO-1) in rats with acute lung rejection and its implication. A valid rat orthotopic left lung transplantation model (SD rat-->Wistar rat) was established by using an improved three-cuff anastomosis technique. The rats were divided into control group, CoPP (HO-1 inducer)-treated group and ZnPP (HO-1 inhibitor)- treated group. The severity of acute rejection was graded on the basis of the morphologic changes of the lung samples stained with HE. The expression of HO-1 protein in lung tissue was detected by using immunohistochemistry and Western blot, and HO-1 mRNA activity was assayed by RT-PCR. The results showed that the expression of HO-1 protein was significantly increased with the acute rejection grading in rats (P<0.01). As compared with control and ZnPP-treated groups, the severity of acute rejection was not alleviated and the grade not reduced significantly in CoPP-treated group (P>0.05). It was concluded that HO-1 protein might be involved in the pathological process of post-graft acute rejection. The expression of HO-1 protein was increased gradually with aggravation of acute rejection, and HO-1 protein might be used as an index to monitor acute rejection after lung transplantation.
Graft Rejection/*enzymology ; Heme Oxygenase (Decyclizing)/genetics ; Heme Oxygenase (Decyclizing)/*metabolism ; Lung Transplantation ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; Rats, Sprague-Dawley ; Rats, Wistar

To investigate the expression of the HO-1 gene in PC12 cells in hypoxic environment and gain further insight to the role of HO-1 in cerebral ischemia, PC12 cells were exposed to hypoxia environment (95% N2, 5% CO2) for 0.5 h, 1 h, 4 h, 8 h, 12 h, 24 h respectively. The level of HO-1 mRNA was examined by reverse transcriptase polymerase chain reaction (RT-PCR); the volume of COHb in the media were measured spectrophotometrically and the cGMP concentration of PC12 cell extracts was determined by radioimmunoassay. We found that after exposure to hypoxia for 1 h, 4 h, 8 h, 12 h, 24 h, HO-1 mRNA increased by 3%, 4%, 17%, 31% 36% as compared with that in control group respectively (P < 0.01 or P < 0.05); the COHb increased by 12%, 29%, 59%, 88%, 94% as compared with that in control group respectively (P < 0.01 or P < 0.05), and the cGMP concentration were 2.2, 3.4, 5.2, 8.1, 10.9-fold as that of the control group (P < 0.01). We are led to conclude that hypoxia induced the expression of HO-1 gene, the production of endogenous CO, and the concentration of cGMP was elevated as well.
Animals ; Carbon Monoxide ; metabolism ; Cell Hypoxia ; Cyclic GMP ; metabolism ; Heme Oxygenase (Decyclizing) ; biosynthesis ; genetics ; Heme Oxygenase-1 ; PC12 Cells ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Up-Regulation