Hemin (ferriprotoporphyrin IX) is shown to form complexes with the chloroquine class of antimalarial drugs. The Soret band of hemin becomes optically active upon the addition of chiral drugs. Results on the hemin-induced quenching of the fluorescence of chloroquine are consistent with the formation of a 2:1 hemin:drug complex with a formation constant of 1.4 x 10(7) at 298 K. Also a direct comp...

This study examined the effect of hemin on the expression of heme oxygenase-1 (HO-1) and monocyte chemoattractant protein-1 (MCP-1) in immortalized rat proximal tubular epithelial cells (IRPTCs). Hemin elicited a dose- and time-dependent induction of HO-1 and MCP-1 mRNA. HO activity contributed to MCP-1 mRNA expression at early time points (4-6 h) because inhibition of HO activity by zinc proto...

Porphyromonas gingivalis is a Gram-negative pathogen associated with the biofilm-mediated disease chronic periodontitis. P. gingivalis biofilm formation is dependent on environmental heme for which P. gingivalis has an obligate requirement as it is unable to synthesize protoporphyrin IX de novo, hence P. gingivalis transports iron and heme liberated from the human host. Homeostasis of a variety...

Treatment of established hypertension, especially for prolonged control of this pathogenic process, represents a great challenge. To upregulate the expression of heme oxygenase (HO) to lower blood pressure (BP) of spontaneously hypertensive rats (SHRs), we administered hemin to 12-week-old adult SHRs through subcutaneously implanted osmotic minipumps for 3 consecutive weeks (the hemin protocol)...

Human mature erythrocyte postribosomal supernatant contains a hemin-reversible translational repressor of globin synthesis as measured in the rabbit reticulocyte cell-free system. Incubation of human supernatant minus hemin at 37” for 2 hours results in conversion of the repressor to a hemin-irreversible form. The presence of 35 pM hemin retards this conversion. Both hemin-reversible and -irrev...

Citr+ Lactococcus lactis subsp. lactis 3022 produced more biomass and converted most of the glucose substrate to diacetyl and acetoin when grown aerobically with hemin and Cu2". The activity of diacetyl synthase was greatly stimulated by the addition of hemin or Cu2+, and the activity of NAD-dependent diacetyl reductase was very high. Hemin did not affect the activities ofNADH oxidase and lacta...

Important progress in our knowledge concerning the biological precursors of hemin was made when Bloch and Rittenberg (1) presented evidence that significant amounts of deuterium are incorporated into the hemin of rats fed deuterioacetic acid. Further advances in this field were made by Shemin and Rittenberg (2-4), who showed that glycine labeled with N15 is utilized as a nitrogenous precursor o...

Gonococcal (GC) agar supplemented with glucose and glutamine was found to be superior to Eugonagar and Trypticase soy agar in demonstrating the hemin requirement of 23 strains of Haemophilus ducreyi by the satellite growth test. The porphyrin test confirmed the requirement for exogenous hematin. With the agar dilution technique, using supplemented GC agar, the hemin concentration required to in...

We have purified a soluble rabbit reticulocyte protein, previously termed the supernatant factor, that reverses the inhibition of protein synthesis in hemin-deficient lysate by promoting the inactivation of the hemin-controlled eIF-2a kinase (HCR) mediating the effect of hemin deficiency. We have identified the supernatant factor as a member of the heat shock protein 70 family, denoted hsp 70(R...