Oxidation products chemical modifications

Unfortunately, there are no universal methods to detect all types of protein oxidation, because the products formed can be so diverse in nature. However, some forms of protein oxidation can be assayed using chemical modification (Davies et al., 1999 Shacter, 2000). In particular, the formation of carbonyl groups on proteins can be targeted using the reagent 2,4-dinitrophenyl-hydrazine (DNPH). This compound reacts with aldehydes to form 2,4-dinitrophenylhydrazone derivatives, which create chromogenic modifications that can be detected at high sensitivity in microplate assays or Western blot analysis (Buss et al., 1997 Winterbourn et al., 1999). 

Tilhnan, A.-M. (1988). Chemical modification of wood products with gaseous alkylene oxides. Journal of Wood Chemistry and Technology, 8(2), 235-259. 

Oxidation Products of Sucrose. The essentially regiospecific oxidation by Agrobacterium tumefaciens, whose dehydrogenase exclusively generates 3 -ketosucrose, is the prototype of an entry reaction into modified sucroses. This ready access opened the way to manifold modifications at the 3 -carbonyl function (Scheme 2.16)." Chemical oxidation proceeds less uniformly, for... 

The catalysts are predominantly modified ZSM-5 zeolite. In general, the modifications are intended to restrict pore mouth size to promote the shape selective production of para-xylene within the microporous structure. The same modifications also serve to remove external acid sites and eliminate the consecutive isomerization of para-xylene. Methods used to modify the zeolite pore openings have included silation [50], incorporation of metal oxides such as MgO, ZnO and P2O5 [51, 52], steaming and the combination of steaming and chemical modification [53]. 

The shortcoming of the reactions of NO with ROS is that the products are also oxidants, although generally of weaker potential than the original ROS. These products (e.g., ONOO-), have been proposed to directly mediate tissue injury (34) by a variety of chemical modifications. A more detailed discussion is given in Section III.B. 

Similarly, chemical modification of Au MeN = COMe)3 also destroys its luminescent behavior. For example none of the oxidation products, Au3Xn(MeN = COMe)3 (n = 2, 4, or 6), shown in Scheme 3 are luminescent [45]. AuT3(MeN = COMe)3 and Au MeN = COMe)3 form several crystalline charge transfer complexes deep yellow Au MeN = COMe 2,4,7-trinitro-9-fluorenone, red AuI3(MeN = COMe)3 - 2,4,5,7-tetra-nitro-9-fluorenone, red Au MeN = COEt)3 2- 2,7-dinitro-9-fluorenone and red Au MeN = COEt)3 2- 2,4,7-trinitro-9-fluorenone [46]. The... 

Protein chemical modification is a problem-solving technique in research and technology. Modifications also occur in natural deteriorations. Generally these modifications are with the most reactive side chains and are predominantly oxidations, reductions, and nucleophilic and electrophilic substitutions. Deteriorations include peptide bond scissions, racemizations, fi-eliminations, and formation of products by the reaction of proteins with added chemicals. Proteins are modified intentionally for structure-function relationship studies or for development of new and improved products. Although appearing quite varied, the techniques used in pharmacological, food and feed, or other industrial areas differ more operationally than from major differences in the levels of chemical sophistication that are used. 

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