Heme enzymes

Studies on the oxygen activation mechanisms by new heme enzymes using hemoprotein mutants and synthetic heme models 96YGK1046. 

Although impressive progress has been made in unraveling the mechanism of ORR catalysis by cofacial porphyrins, much remains to be learned before we can understand how this mechanism relates to those in heme enzymes and simple metalloporphyrins and use our mechanistic knowledge to rationally design improved metalloporphyrin catalysts for the ORR. 

Taraban, M.B., Leshina, T.V., Anderson, M.A., and Grissom, C.B., Magnetic field dependence of electron transfer and the role of electron spin in heme enzymes horseradish peroxidase, J. Am. Chem. Soc.,... 

Gosh et al. reported LDA(SVWN) studies of oxo(porphyrinato)iron(IV) complexes.83 These compounds have been detected in various peroxidases and are believed to be involved in the reaction mechanisms of other heme enzymes, such as cytochromes P450. Very Good Fe-0 distance and values of unsealed stretching frequencies, which were in excellent agreement with CASSCF results, published elsewhere, were obtained. 

A quite different approach came from Chance and others using heme enzymes (1947). Purified horseradish peroxidase has a characteristic absorption spectrum which was visibly altered in the presence of hydrogen peroxide. When an appropriate substrate was added it was oxidized by the hydrogen peroxide and the spectrum reverted to that of the original state of the enzyme. Similar studies were performed with catalase, showing that prosthetic groups in enzymes underwent reversible changes in the course of their reactions. 

Structures of Gas-Generating Heme Enzymes Nitric Oxide Synthase and Heme Oxygenase... 

The heme enzyme chloroperoxidase (CPO), produced by the marine fungus Caldariomycesfumago, is a versatile enzyme which exhibits a broad spectrum of chemical reactivities and it is recognized as a most promising biocatalyst for synthetic applications. Recently, pure (R)-phenyl methylsulfoxide (ee > 99 %) was prepared by chemo- and stereo-selective oxidation of phenyl methylsulfide with CPO in citrate buffer-ionic liquid mixtures. ... 

He teaches courses in bioorganic and bioinorganic chemistry (in particular on the role of metals in biology and on the iron-heme enzymes such as peroxidases and cytochromes P-450 monooxygenases). 

Peroxidases (E.C. 1.11.1.7) are ubiquitously found in plants, microorganisms and animals. They are either named after their sources, for example, horseradish peroxidase and lacto- or myeloperoxidase, or akin to their substrates, such as cytochrome c, chloro- or lignin peroxidases. Most of the peroxidases studied so far are heme enzymes with ferric protoporphyrin IX (protoheme) as the prosthetic group (Fig. 1). However, the active centers of some peroxidases also contain selenium (glutathione peroxidase) [7], vanadium (bromoperoxidase)... 

STRUCTURES OF GAS-GENERATING HEME ENZYMES NITRIC OXIDE SYNTHASE AND HEME OXYGENASE... 

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