High-throughput capillary electrophoresis method for plasma cysteinylglycine measurement: evidences for a clinical application

Increased levels in plasma homocysteine and cysteine, and more recently, decreased levels in cysteinylglycine have been indicated as a risk factor for vascular diseases. Most assays focused their attention only on homocysteine determination and when also other thiols were measured, analytical times...

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Bibliographic Details
Published in:Amino acids 2008, Vol.34 (1), p.69-74
Main Authors: Zinellu, A., Pinna, A., Zinellu, E., Sotgia, S., Deiana, L., Carru, C.
Format: Article
Language:English
Subjects:
Amino acids
Analytical Chemistry
Biochemical Engineering
Biochemistry
Biomedical and Life Sciences
Capillarity
Cartridges
Chromatography, High Pressure Liquid
Dipeptides - blood
Diseases
Electrophoresis
Electrophoresis, Capillary - methods
Female
Homocysteine
Humans
Life Sciences
Male
Middle Aged
Neurobiology
Patients
Plasma
Proteomics
Retinal Vein Occlusion - blood
Risk
Thiols
Time Factors
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Summary:Increased levels in plasma homocysteine and cysteine, and more recently, decreased levels in cysteinylglycine have been indicated as a risk factor for vascular diseases. Most assays focused their attention only on homocysteine determination and when also other thiols were measured, analytical times drastically increased. By modifying our previous method for thiols detection, we set up a rapid capillary electrophoresis method for the selective quantification of plasma cysteinylglycine, cutting the analysis time of about 50%. Samples were treated with tri-n-butylphosphine as reducing agent, proteins were precipitated with trichloroacetic acid and released thiols were successively derivatized by the selective thiol laser-induced fluorescence-labeling agent 5-iodoacetamidofluorescein and separated by capillary electrophoresis. A baseline separation between peaks was obtained in about 2 min using 3 mmol/L sodium phosphate/2.5 mmol/L boric acid as electrolyte solution with 75 mmol/L N-methyl-D-glucamine at pH 11.25 in a 47 cm long capillary with a cartridge temperature of 45 °C. The method application was checked by measuring plasma Cys-Gly levels in a group of patients affected by retinal vein occlusion (RVO), an important cause of visual loss in the elderly. The low levels of Cys-Gly found in the RVO patients suggest that these small thiols may have importance in the disease development.
ISSN:0939-4451
1438-2199
DOI:10.1007/s00726-007-0590-4