Heme-based mechanism

Other enzyme-based mechanisms. Furthermore, the epimers of artemether showed nearly equal in vivo activity (1.02 mg/kg of body weight for a epimer versus 1.42 mg/kg of body weight for the P epimer), making the heme-based mechanism preferable over the SERCA-based mechanism for which a greater disparity in the activities would be expected. Whatever the situation may be, we all agree that further studies are necessary to clarify, or to unambiguously determine the real mechanism of action of this family of compounds. 

Although it is clear in model systems that artemisinin can efficiently alkylate heme-based models, the role of this event in the mechanism of action of artemisinin has... 

Jin S, Kurtz DM, Liu ZJ, Rose J, Wang BC (2002) X-ray crystal structures of reduced rubr-erythrin and its azide adduct a structure-based mechanism for a non-heme diiron peroxidase. J Am Chem Soc 124 9845-9855... 

In the case of beef liver catalase, distal histidine (His74) is believed to serve as a general acid-base catalyst to facilitate the heterolytic 0—0 bond of hydroperoxide bound to the heme (Scheme 2) (21). The Asnl47 residue located near the heme could assist the heterolysis by making the distal site into a polar atmosphere. The same acid-base mechanism has been attributed to peroxidases... 

Mechanism for transduction of the ligand-binding signal in heme-based gas sensory proteins revealed by resonance Raman spectroscopy 05ACR662. 

Are the Critical Ion Pairs for Quaternary Structural Change Within Reach of the Heme-based Consilient Mechanism ... 

Convincing evidence for a metal-based mechanism in non-heme catalyzed C-H oxidation reactions with a synthetic catalyst appeared in 1997 in work by Que and co-workers [38] where a family of tpa-based (tpa = tris-(2-pyridylmethyl)amine) iron(ll) complexes were investigated as stereospecific C-H oxidation catalysts using H2O2 as oxidant. Beyond their mechanistic significance, these findings were key for the future development of this chemistry with a synthetic aim, because a metal-based mechanism bears implicitly the possibility of modulating the... 

Based on the well-studied catalytic mechanism in series 2 metalloporphyrins (Fig. 18.20), further developments of the heme/imidazole motif in the context of fuel cell catalysis have to be directed towards the following ... 

It has been said above that cyt c was one of the most important and extensively studied electron-transfer proteins with active heme centers. Thus, cyt c was widely used in enzyme-based biosensors and to study the mechanism of the catalytic process between redox enzyme and substrate. 

He, K., Falick, A.M., Chen, B., Nilsson, F. and Correia, M.A. (1996) Identification of the heme adduct and an active site peptide modified during mechanism-based inactivation of rat liver cytochrome P450 2B1 by secobarbital. Chemical Research in Toxicology, 9 (3), 614-622. 

The mechanism in Fig. 14 applies equally well to both PVC and HPll. However, an unusual bond between the imidazole ring of His392 and the p-carbon of Tyr415 on the proximal side of the HPll heme has been identified (Fig. 13) (93), and subsequently its presence was correlated with heme oxidation. The apparent correlation between heme oxidation and His-Tyr bond formation suggested a mechanistic linkage between the two modifications and an alternate mechanism imique to HPll was proposed (Fig. 15). As with the first mechanism, the reaction assumes the formation of compound I that is available for reduction. Formation of the His-Tyr bond, involving a base catalyzed proton extraction from the... 

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