Heme proteins Hemerythrin

Hemerythrin and myohemerythrin have roles as oxygen carriers in marine invertebrates, a function similar to that of the heme proteins hemoglobin and myoglobin in mammals and the copper-protein hemo-cyanin in mollusks and arthropods 1-7, 13). 

Hemerythrin, which contains iron, and hemocyanin, which contains copper, are nonheme oxygen-carrying proteins in which the metal appears to be bound directly to the protein via the functional groupings of one or more amino acid residues. The metal to oxygen ratio appears to be 2 1 in both hemerythrin and hemocyanin in contrast to the 1 1 ratio found in the heme proteins (13, 23, 26). 

Heme proteins, 262 electron transport, 263 Hemerythrin, 253 Hemin ester, 1266 Hemoglobin, 262,1257,1269 artificial, 100... 

Proton-coupled electron transfer (PCET) is known to play an important role in a variety of biological processes, including microbial iron transport by ferric enterobactin, enzyme catalysis in systems such as fumarate reductase and nitrate reducatase, and dioxygen binding by the non-heme iron protein hemerythrin. " As such, pH-dependent electrochemical studies can play an important role in unraveling these mechanisms. The most heavily studied biological system known to involve PCET is cytochrome c oxidase, the terminal electron-transfer complex of the mitochondrial respiratory chain, which catalyzes the reduction of molecular oxygen to water. ... 

Gofactors. Frequendy proteins exist in their native state in association with other nonprotein molecules or cofactors, which are cmcial to their function. These may be simple metal ions, such as Fe " in hemerythrin or Ca " in calmodulin a heme group, as for the globins nucleotides, as for dehydrogenases, etc. 

The hemerythrin of Golfingia gouldii consists of eight subunits, each of which contains two iron atoms, in a protein with molecular weight 108,000. Spectral and magnetic data point to an oxo-bridged structure around the non-heme iron atom (99). Protein B2 of ribotide reductase of E. coli has some properties in common with hemerythrin presumably a protein corresponding to that of E. coli reduces ribotides in animal tissues, a conclusion based on probes with inhibitors. 

Like hemerythrin, hemocyanin is an oxygen transport non-heme-containing protein found in some arthropods and molluscs (104,105). In the 02-bound form, hemocyanin contains an antiferromagnetically coupled binuclear copper(II) system (106) ligated by histidine residues, with a sideways / 2-v2 V2 peroxo group bound to both Cu11 centers (104), which superseded the previous model (107). 

This article will limit its view to hemoproteins and heme prosthetic groups, the iron-sulfur proteins, and hemerythrin. Mossbauer spectro-... 

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