title: Human serum albumin cysteinylation is increased in end stage renal disease patients and reduced by hemodialysis: mass spectrometry studies.
abstract: The aim of the present work was to monitor the covalent modifications of human serum albumin (HSA) in end stage renal diseases (ESRD) non-diabetic patients, before and after hemodialysis (HD), by direct infusion electrospray mass spectrometry (ESI-MS). Human serum samples were collected from healthy subjects (n = 10, 20-60 yr) and age-matched ESRD patients (n = 8) before and after HD, purified by affinity chromatography and analyzed by a triple-quadrupole mass spectrometer. The deconvoluted spectra from healthy subjects were all characterized by three peaks attributed to non-glycated mercaptoalbumin (HSA-SH) and to the corresponding adducts with cysteine (HSA-Cys) and glucose (HSA-Glc); relative contents: mercaptoalbumin in both glycated and non-glycated form, HSA-SHt (74 ± 6%), HSA-Cys (26 ± 5%) and HSA-Glc (24 ± 3%). HSA isolated from ESRD patients before HD was characterized by a significant reduction of HSA-SHt (42 ± 7%), and by a concomitant increase of the HSA-Cys adduct (58 ± 7%). Hemodialysis significantly reduced the cysteinylated form (37 ± 7%) and restored HSA-SHt (63 ± 8%) in all the ESRD patients. The mechanism of thiol oxidation and cysteinylation was then studied by mass spectrometry, using LQQCPF as a model peptide and H(2)O(2) as an oxidizing agent.
authors.affiliation: Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Regazzoni
authors.forename: L
authors.initials: L
authors.lastname: Del Vecchio
authors.forename: A
authors.initials: A
authors.lastname: Altomare
authors.forename: K-J
authors.initials: KJ
authors.lastname: Yeum
authors.forename: D
authors.initials: D
authors.lastname: Cusi
authors.forename: F
authors.initials: F
authors.lastname: Locatelli
authors.forename: M
authors.initials: M
authors.lastname: Carini
authors.forename: G
authors.initials: G
authors.lastname: Aldini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003545:Cysteine / Q000378:metabolism; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D012015:Reference Standards; D006435:Renal Dialysis; D012709:Serum Albumin / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000592:standards; D055815:Young Adult
chemical_list: D010446:Peptide Fragments; D012709:Serum Albumin; D003545:Cysteine