Heme-Based Molecules

Simple heme-containing oxygen sensing molecules that respond to environmental changes are 

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FIGURE 15. Electron transfer pathways in FCB2. The best path for electron transfer from flavin to heme based on GREENPATH calculations. Dashed lines represent paths along hydrogen bonds and dotted lines represent a through-space jump. Path 1 involves a water molecule while path 2 does not. 

In correlation with the nature of compounds that can induce ARE-driven transcription, many of the proteins whose expression is mediated by the ARE have an endogenous role in regulating cellular redox status and protecting the cell from oxidative damage. Enzymes such as GST, NQOl, and HO-1 function to detoxify harmful by-products of oxidative stress, including lipid and DNA base hydroperoxides (29,30), quinones (31), and heme-containing molecules (32). The induction of enzymes involved in GSH biosynthesis leads to an increase in cellular GSH levels that provides a buffer against oxidative insult (2). 

Recent developments in manganese corrole chemistry 13CCR1306. Reductive N—N coupling of NO molecules on transition metal heme-based complexes leading to N2O 12CCR468. 

Detection by LDMS and structural elucidation of other secondary metabolite products, generated in the host during the onset of the parasite disease, is discussed. These molecules may serve as additional biomarkers for rapid malaria diagnosis by LDMS. For instance, choline phosphate (CP) is identified as the source of several low-mass ions observed in parasite-infected blood samples in addition to heme biomarker ions. The CP levels track the sample parasitemia levels. This biomarker can provide additional specificity and sensitivity when compared to malaria detection based on heme ion signals alone. Furthermore the observed elevated CP levels are discussed in the context of Plasmodium metabolism during its intra-erythrocytic life cycle. These data can... 

The chlorophyll molecule comprises a central magnesium ion surrounded by an organic nitrogen-containing cyclic structure called haem (or heme ), (V) which is based on a porphyrin ring. 

Once the protein interaction pattern is translated from Cartesian coordinates into distances from the reactive center of the enzyme and the structure of the ligand has been described with similar fingerprints, both sets of descriptors can be compared [25]. The hydrophobic complementarity, the complementarity of charges and H-bonds for the protein and the substrates are all computed using Carbo similarity indices [26]. The prediction of the site of metabolism (either in CYP or in UGT) is based on the hypothesis that the distance between the reactive center on the protein (iron atom in the heme group or the phosphorous atom in UDP) and the interaction points in the protein cavity (GRID-MIF) should correlate to the distance between the reactive center of the molecule (i.e. positions of hydrogen atoms and heteroatoms) and the position of the different atom types in the molecule [27]. 

The changes in pKa between the aqueous solutions and the micelles must therefore arise from the hydrophobic interactions inside the micelle [27, 31]. In general, the pKa in the micelle is lower than that in its absence, implying that the water molecule inside the micelle is more acidic than that outside. The effect of the hydrophobic interaction of the micellar cavity is further evident in the trend of variation of the pKa with micelle (see Table 1). For all the complexes, the pKa increases in the order anionic SDS > neutral TX-lOO > cationic CTAB. The trend is consistent with the expectation based on consideration of the electrostatic charges in the Stem layer. The anionic SDS micelle, in comparison with CTAB and TX-lOO, stabilizes positive charge on the cationic aqua (pyridinato) ferric heme complexes, and therefore exhibits higher pKa. 

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