A rapid LC-FTMS method for the analysis of cysteine, cystine and cysteine/cystine steady-state redox potential in human plasma.
BACKGROUND
The steady-state redox potential of the cysteine/cystine couple in human plasma provides a measure of oxidative stress, yet available assays are limited by either specificity or speed of assay.


METHODS
The present study evaluated the use of LC-FTMS for identification based on accurate mass combined with quantification by stable isotopic dilution to rapidly determine cysteine and cystine concentration and cysteine/cystine steady-state redox potential in human plasma.


RESULTS
A simple extraction procedure followed by a rapid LC separation eluted cysteine in 4 min and cystine in 1.5 min with simultaneous measurement of glutathione (GSH) and glutathione disulfide (GSSG). A study of five young (mean age=25.7) subjects and 5 older (mean age=67.8 y) subjects showed an increased oxidation with age.


CONCLUSIONS
The analysis by LC-FTMS is suitable for high-throughput analysis of plasma cysteine, cystine and cysteine/cystine steady-state redox potential as clinical measures of oxidative stress.
Johnson
Jennifer M
JM
Department of Medicine, Division of Pulmonary, Allergy and Critical Care, Emory University, Atlanta, GA 30322, USA.
Strobel
Fredrick H
FH
Reed
Matthew
M
Pohl
Jan
J
Jones
Dean P
DP
D003553:Cystine / Q000097:blood* / Q000737:chemistry; D003619:Dansyl Compounds; D004220:Disulfides / Q000097:blood* / Q000737:chemistry; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D003619:Dansyl Compounds; D004220:Disulfides; D003553:Cystine; C029038:dansyl chloride