Damage to proteins

Davies, M. J. (2003). Singlet oxygen-mediated damage to proteins and its consequences. 

Hoare M, Khan MR, DunnUl P (1992) Interfacial damage to proteins during intensive mixing in fermentation and down stream process. In Van Den Tweei WJJ, Harder A, Buitelaar RM (eds) StabUity and stabilization of enzymes, Proc Inter Sym, The Netherland, Elsevier Sci... 

Davies, M.J., Fu, S., Wang, H., and Dean, R.T. (1999) Stable markers of oxidant damage to proteins and their application in the study of human disease. Free Radio Biol. Med. 27, 1151-1163. 

Zitiianova and others (2006) examined the inhibitory effect of extracts from different kinds of fruits and vegetables on the oxidative damage to proteins in vitro. Dragsted and others (2004) investigated the relative influence of nutritive and nonnutritive factors in fruit and vegetables on oxidative damage and enzymatic defense. Jacob and others... 

The concentration of ubiquitin increases in injured cells, and any damaged proteins are removed by reaction with ubiquitin. It also increases in trauma, which may be a protective mechanism responding to die increased likelihood of damage to proteins. 

Sitte, N. (2003). Oxidative damage to proteins. In "Aging at the Molecular Level" (T. von Zglinicki, ed.), pp. 27-45. Kluwer Academic Publishers, The Netherlands. 

A.T. Rotta, B. Gunnarsson, L.J. Hernan, B.P. Fuhrman, D.M. Steinhorn, Partial liquid ventilation with perflubron attenuates in vivo oxidative damage to proteins and lipids, Crit. Care Med. 28 (2000) 202-208. 

More generally, one-electron oxidation of protein-bound phenols to form reactive ary-loxyl radicals is a possible pro-oxidant mechanism since these radicals can propagate H-atom or electron transfers within the protein. In addition to phenol protein covalent coupling, these phenol-mediated oxidative damages to proteins could be detrimental to their function as enzymes, receptors, and membrane transporters. For instance, investigations by capillary electrophoresis have shown that quercetin in concentrations lower than 25 pM potentiates HSA degradation by AAPH-derived peroxyl radicals. 

Salvi, A. et ah. Structural damage to proteins caused by free radicals assessment, protection by antioxidants, and influence of protein binding, Biochem. Pharmacol., 61, 1237, 2001. 

Reznick A, Packer L (1994) Oxidative damage to proteins spectrophotometric method for carbonyl assay. Methods Enzymol 233 357-363... 

Chemical reactivity can be a two-edged sword for toxicity. It can be beneficial if the parent chemical quickly reacts and degrades to either more benign or more easily cleared products. However, reactivity can be harmful if the reactions lead to damage to proteins or DNA. This is the case discussed here. One type of reactivity-mediated toxicity is skin sensitization caused when a low molecular weight compound penetrates into the epidermis and covalently reacts with an underlying protein. 

If a large amount of the toxic substance is present, then the detoxication processes present are overwhelmed. Excess super oxide is produced, reduced GSH and NADPH are depleted, and hydroxyl radicals and singlet oxygen are formed. This is the condition known as oxidative stress (see also below this chapter). As well as causing lipid peroxidation, ROS will also cause DNA damage and damage to proteins. 

Thus, as previously discussed, hydroxyl radical can initiate lipid peroxidation, generating free radicals as well as directly damaging DNA. Oxidative damage to proteins yields lipofuscin, which is known to accumulate in rodent liver treated with peroxisomal proliferators. Treatment with antioxidants will inhibit the liver cancer. 

Why do we age This question is often asked but the answers are not simple. Do our tissues deteriorate with age as a result of damage to proteins From an accumulation of mutations in our DNA From attacks by free radicals From loss of hormone receptors From misregulation of mitosis 487 From loss of telomeres on the ends of replicating DNA (Chapter 27, Section Q8) 488 489 From an internal genetic program that dictates our life span All of these possibilities may be partially correct. The simple answer is that "we just wear out." However, different parts wear out at different rates and in different ways. 

Symons MCR (1999) Mechanism of radiation damage to proteins and DNA - an EPR perspective. Progr Reaction Kinet Mechanism 24 139-164... 

Patton, A. R. Present status of heat-processing damage to protein foods. Nutr. Rev. 1950, 5, 193-6. 

H8. Haycock, J. W., Ralston, D. R., Morris, B., Freedlander, E., and MacNeil, S., Oxidative damage to protein and alterations to antioxidant levels in human cutaneous thermal injury. Bums 23, 533-540 (1997). 

Heavy metal ions test. Heavy metal ions precipitate proteins from solution. The ions that are most commonly used for protein precipitation are Zn2+, Fe3+, Cu2+, Sb3+, Ag+, Cd2+, and Pb2+. Among these metal ions, Hg2+, Cd2+, and Pb2+ are known for their notorious toxicity to humans. They can cause serious damage to proteins (especially... 

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