Several biomarkers of oxidative stress have been proposed and used in clinical research but so far unreliable or, at least, controversial results have been obtained. Given the high susceptibility of sulfhydryl groups to oxidation, we here suggest the use of a protein thiolation index (PTI), i.e., the molar ratio between the sum of all low molecular mass thiols bound to plasma proteins (forming, as a whole, S-thiolated proteins and protein free cysteinyl residues, as a suitable biomarker of oxidative stress. While titration of free thiols can be performed by a simple spectrophotometric procedure, accurate quantification of S-thiolated proteins is problematic and current methods require, in most cases, application of time-consuming chromatographic techniques, making their application to large-scale clinical studies difficult. Here we report a new spectrophotometric method whichr elies on the specific determination of low molecular mass thiols released from S-thiolated proteins afterd ithiothreitol reduction. These amino acids can be titrated by conjugation with ninhydrin which, reactingwith primary and secondary amine groups, yields a deep blue-purple color, which can be spectrophotometrically revealed. PTI showed an age dependency with a near linear increase during aging in humans. In addition, PTI was significantly higher in patients suffering from alkaptonuria with respect to healthy controls, suggesting that increased prooxidant conditions occur in the blood of these subjects.
Protein thiolation index (PTI) as a biomarker of oxidative stress / D. Giustarini, I. Dalle Donne, S. Lorenzini, E. Selvi, G. Colombo, A. Milzani, P. Fanti, R. Rossi. - In: FREE RADICAL BIOLOGY & MEDICINE. - ISSN 0891-5849. - 53:4(2012 Aug 15), pp. 907-915.
Protein thiolation index (PTI) as a biomarker of oxidative stress
I. Dalle Donne;G. Colombo;A. Milzani;
2012
Abstract
Several biomarkers of oxidative stress have been proposed and used in clinical research but so far unreliable or, at least, controversial results have been obtained. Given the high susceptibility of sulfhydryl groups to oxidation, we here suggest the use of a protein thiolation index (PTI), i.e., the molar ratio between the sum of all low molecular mass thiols bound to plasma proteins (forming, as a whole, S-thiolated proteins and protein free cysteinyl residues, as a suitable biomarker of oxidative stress. While titration of free thiols can be performed by a simple spectrophotometric procedure, accurate quantification of S-thiolated proteins is problematic and current methods require, in most cases, application of time-consuming chromatographic techniques, making their application to large-scale clinical studies difficult. Here we report a new spectrophotometric method whichr elies on the specific determination of low molecular mass thiols released from S-thiolated proteins afterd ithiothreitol reduction. These amino acids can be titrated by conjugation with ninhydrin which, reactingwith primary and secondary amine groups, yields a deep blue-purple color, which can be spectrophotometrically revealed. PTI showed an age dependency with a near linear increase during aging in humans. In addition, PTI was significantly higher in patients suffering from alkaptonuria with respect to healthy controls, suggesting that increased prooxidant conditions occur in the blood of these subjects.File | Dimensione | Formato | |
---|---|---|---|
12 Giustarini 2012 FRBM.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
858.21 kB
Formato
Adobe PDF
|
858.21 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.