title: Tandem mass spectrometry assays of palmitoyl protein thioesterase 1 and tripeptidyl peptidase activity in dried blood spots for the detection of neuronal ceroid lipofuscinoses in newborns.
abstract: We report new substrates for quantitative enzyme activity measurements of human palmitoyl protein thioesterase (PPT1) and tripeptidyl peptidase (TPP1) in dried blood spots from newborns using tandem mass spectrometry. Deficiencies in these enzyme activities due to inborn errors of metabolism cause neuronal ceroid lipofuscinoses. The assays use synthetic compounds that were designed to mimic the natural substrates. Incubation produces nanomole quantities of enzymatic products per a blood spot that are quantified by tandem mass spectrometry using synthetic internal standards and selected reaction monitoring. The assays utilize a minimum steps for sample workup and can be run in a duplex format for the detection of neuronal ceroid lipofuscinoses or potentially multiplexed with other mass spectrometry-based assays for newborn screening of lysosomal storage disorders.
authors.affiliation: Departments of Chemistry, ‡Pediatrics, and §Biochemistry, University of Washington , Seattle, Washington 98115-1700, United States.
authors.forename: Mariana
authors.initials: M
authors.lastname: Barcenas
authors.forename: Chang
authors.initials: C
authors.lastname: Xue
authors.forename: Tatyana
authors.initials: T
authors.lastname: Marushchak-Vlaskin
authors.forename: C Ronald
authors.initials: CR
authors.lastname: Scott
authors.forename: Michael H
authors.initials: MH
authors.lastname: Gelb
authors.forename: František
authors.initials: F
authors.lastname: Tureček
mesh_terms: D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D009472:Neuronal Ceroid-Lipofuscinoses / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D012015:Reference Standards; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013869:Thiolester Hydrolases / Q000097:blood*; D000091346:Tripeptidyl-Peptidase 1
chemical_list: D000091346:Tripeptidyl-Peptidase 1; D013869:Thiolester Hydrolases; C095299:palmitoyl-protein thioesterase; C000717267:TPP1 protein, human