We have previously reported that CYP3A cross-links with polyubiquitinated proteins in microsomes from nicardipine-treated rats in a process that is distinct from classical polyubiquitination. To further examine the role of the proteasome in CYP3A degradation, we investigated the effects of proteasome inhibitors lactacystin, MG132, proteasome inhibitor 1, and hemin in primary cultures of rat and...

Heme prosthetic groups are vital for all living organisms, but they can also promote cellular injury by generating reactive oxygen species. Therefore, intestinal heme absorption and distribution should be carefully regulated. Although a human intestine brush-border heme receptor/transporter has been suggested, the mechanism by which heme crosses the apical membrane is unknown. After it enters t...

Hemin induces nonterminal differentiation of human K562 erythroleukemia cells, which is accompanied by the expression of certain erythroid cell-specific genes, such as the embryonic and fetal globins, and elevated expression of the stress genes hsp70, hsp90, and grp78/BiP. Previous studies revealed that, as during heat shock, transcriptional induction of hsp70 in hemin-treated cells is mediated...

An iron-fortified whey protein concentrate (Fe-WPC) was prepared by addition of ferric chloride to concentrated whey. A large part of the iron in the Fe-WPC existed as complexes with proteins such as β-lactoglobulin. The bioavailability of iron from FeWPC was evaluated using iron-deficient rats, in comparison with heme iron. Rats were separated into a control group and an irondeficiency group. ...

The role of hemin in the maintenance of protein synthesis in reticulocyte lysates was examined by comparing the effects of various porphyrins and metalloporphyrins on the protein kinase activity of the hemin-controlled repressor and on protein synthesis. The porphyrin requirements for maintenance of protein synthesis were relatively specific. Iron and cobalt metalloporphyrins sustained protein ...

Previous characterization of hemophores from Serratia marcescens (HasAs), Pseudomonas aeruginosa (HasAp), and Yersinia pestis (HasAyp) showed that hemin binds between two loops, where it is axially coordinated by H32 and Y75. The Y75 loop is structurally conserved in all three hemophores and harbors conserved ligand Y75. The other loop contains H32 in HasAs and HasAp, but a noncoordinating Q32 ...

Induction of heme oxygenase-1 (HO-1) in renal tubules occurs as an adaptive and beneficial response in acute renal failure (ARF) following ischemia and nephrotoxins. Using an in vitro model of polarized Madin-Darby canine kidney (MDCK) epithelial cells, we examined apical and basolateral cell surface sensitivity to HO-1 induction by heme. Basolateral exposure to 5 microM hemin (heme chloride) r...

The formation of translational inhibitor (active eIF-2 kinase) from proinhibitor (inactive eIF-2 kinase) in reticulocyte lysates, known to be controlled by hemin, can, as we recently reported, be induced by 3':5'-cyclic AMP(cAMP)-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) or its catalytic subunit. We find that in crude preparations from rabbit reticulocyte lysates, h...

Degradation of dyes is an important environmental issue. In order to avoid the carcinogenic risks in anaerobic-aerobic biological process for wastewater containing azo dyes, a hemin based biomimetic oxidative degradation of azo dyes was developed. Acid orange 7 (AO7) was selected as the model for azo dye and the high efficient degradation was achieved in hemin/H2O2 system at pH 11.0. Degradatio...

Hemin is the product of hemoglobin oxidation. Some diseases may lead to a formation of hemin. The accumulation of hemin causes destruction of red blood cells (RBC) membranes. In this study the process of development of topological defects of RBC membranes within the size range from nanoscale to microscale levels is shown. The formation of the grain-like structures in the membrane ("grains") wit...