Non-heme proteins

There is now sufficient information in the literature to conclude that nitrite reacts with the non-heme proteins of meat. 

Several techniques have now been developed for completely removing the iron from non-heme proteins, replacing the iron and reconstituting their chemical activity. The most effective method is to use the mercurial. 

Model Compounds Very few ferrous complexes having non-porphyrin ligands react with dioxygen to form stable adducts. Unlike the pseudo-heme model complexes, all of the adducts prepared so far appear to be peroxo rather than superoxo species. To mimic the protein fragment on the non-heme proteins multidentate... 

Iron Fe 26 Constituent of cytochromes and other heme or non-heme proteins, cofactor for a number of enzymes... 

A fourth complex connects site 1 to site 2. Thus, the first complex in the chain consists of the enzyme NADH dehydrogenase and a group of around five closely linked proteins that contain electron-rich iron-sulphur clusters. These are non-heme proteins vital to the flow of electrons through the chain. The second complex consists of the enzyme succinate dehydrogenase and its collection of iron-sulphur proteins. The third complex contains the hemoproteins cytochromes b and Cj, and one iron-sulphur protein. The final complex, the one that actually reduces oxygen to water, is called cytochrome oxidase and contains two heme groups (heme a and heme a ) and two copper centres. Ubiquinone, also known as coenzyme Q, is a lipid-soluble quinone which connects the first, second, and third complexes. Cytochrome c is the electron carrier hemoprotein that links the complexes of site 2 to cytochrome oxidase in site 3. 

Phosphorescent inclusion complex can be used to probe heme accessibihty in heme proteins [27]. The phosphorescence lifetime of 6-bromo-2-naphthyl sulfate (BNS) is several hundred microseconds and is self-quenched. Quenching of BNS phosphorescence does not occur for the non-heme protein lysoz3me and apomyoglobin but occurs by a dynamic mechanism with a quenching constant of 12 X lO M s for cytochrome c and myoglobin and with a quenching constant of 6.2 x 10 s for protoporphyrin IX. The phosphorescence of... 

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