Protein Carbonyl Content

About: Protein Carbonyl Content is a research topic. Over the lifetime, 206 publications have been published within this topic receiving 22565 citations.

Determination of carbonyl content in oxidatively modified proteins.

Abstract: Publisher Summary This chapter discusses methods to determine carbonyl content in oxidatively modified proteins. The methods described are (1) reduction of the carbonyl group to an alcohol with tritiated borohydride; (2) reaction of the carbonyl group with 2,4-dinitrophenylhydrazine to form the 2,4-dinitrophenylhydrazone; (3) reaction of the carbonyl with fluorescein thiosemicarbazide to form the thiosemicarbazone; and (4) reaction of the carbonyl group with fluorescein amine to form a Schiff base followed by reduction to the secondary amine with cyanoborohydride. Van Poelje and Snell have also quantitated protein-bound pyruvoyl groups through formation of a Schiff base with p-aminobenzoic acid followed by reduction with cyanoborohydride. Although a systematic investigation has not appeared, this method should also be useful in detecting other protein-bound carbonyl groups. Carbonyl content of proteins is expressed as moles carbonyl/mole subunit for purified proteins of known molecular weight. For extracts, the results may be given as nanomoles carbonyl/milligram protein. For a protein having a molecular weight of 50,000, a carbonyl content of 1 mol carbonyl/mol protein corresponds to 20 nmol carbonyl/mg proteins.

Carbonyl assays for determination of oxidatively modified proteins

Abstract: Publisher Summary Enzymes and structural proteins may be attacked whenever free radicals are generated. As a consequence, oxidative modification of proteins may occur in a variety of physiologic and pathologic processes. Although the distinction is sometimes arbitrary, these modifications may be primary or secondary. Primary modifications occur in metal-catalyzed oxidation, radiation-mediated oxidation, and oxidation by ozone or oxides of nitrogen. Secondary modifications occur when proteins are modified by molecules generated by oxidation of other molecules. One important example is the covalent modification of proteins by hydroxynonenal produced by oxidation of lipids. Carbonyl groups (aldehydes and ketones) may be introduced into proteins by any of these reactions, and the appearance of such carbonyl groups is taken as presumptive evidence of oxidative modification. Assay of carbonyl groups in proteins provides a convenient technique for detecting and quantifying oxidative modification of proteins. This chapter presents new methods for determination of carbonyl content, which are based on the reaction of carbonyl groups with 2,4-dinitrophenylhydrazine to form a 2,4-dinitrophenylhydrazone. The assays provide substantial improvements in both sensitivity and specificity.

Oxidative damage to proteins : spectrophotometric method for carbonyl assay

Abstract: Publisher Summary Oxygen radicals are implicated as an important cause of oxidative modification of proteins which may lead to their rapid degradation. Among the various oxidative modifications of amino acids in proteins, carbonyl formation may be an early marker for protein oxidation. This type of alteration is characterized as metal-catalyzed oxidation of proteins. The molecular mechanisms of this type of protein oxidation are discussed in this chapter. Redox cycling cations, such as Fe 2+ or Cu 2+ can bind to cation binding locations on proteins and with the aid of further attack by H 2 O 2 or O 2 can transform side-chain amine groups on several amino acids into carbonyls. The most likely amino acid residues to form carbonyl derivatives are lysine, arginine, proline, and histidine. Metal-catalyzed oxidation of proteins is not necessarily the only mechanism by which carbonyls are introduced into proteins. The chapter discusses the physiological importance of protein oxidation. Increases in carbonyl levels are examined in several diseases, such as rheumatoid arthritis, ischemia-reperfusion injury to heart muscles, and muscle damage caused by exhaustive exercise.

Brain Regional Correspondence Between Alzheimer's Disease Histopathology and Biomarkers of Protein Oxidation

Abstract: Four biomarkers of neuronal protein oxidation [W/S ratio of MAL-6 spin-labeled synaptosomes, phenylhydrazine-reactive protein carbonyl content, glutamine synthetase (GS) activity, creatine kinase (CK) activity] in three brain regions [cerebellum, inferior parietal lobule (IPL), and hippocampus (HIP)] of Alzheimer's disease (AD)-demented and age-matched control subjects were assessed. These endpoints indicate that AD brain protein may be more oxidized than that of control subjects. The W/S ratios of AD hippocampal and inferior parietal synaptosomes are 30 and 46% lower, respectively, than corresponding values of tissue isolated from control brain; however, the difference between the W/S ratios of AD and control cerebellar synaptosomes is not significant. Protein carbonyl content is increased 42 and 37% in the Alzheimer's HIP and IPL regions, respectively, relative to AD cerebellum, whereas carbonyl content in control HIP and IPL is similar to that of control cerebellum. GS activity decreases an average of 27% in the AD brain; CK activity declines by 80%. The brain regional variation of these oxidation-sensitive biomarkers corresponds to established histopathological features of AD (senile plaque and neurofibrillary tangle densities) and is paralleled by an increase in immunoreactive microglia. These data indicate that senile plaque-dense regions of the AD brain may represent environments of elevated oxidative stress.