Serum has been the logical choice and most-used bio-specimen for monitoring biomarkers. However, direct analysis of low-abundance biomarkers in serum is still a problem. Here, we have established a directed mass spectrometry (inclusion list driven MS) method, Direct-S, for direct quantification of protein biomarkers in native serum samples without high-abundance protein depletion or pre-fractionation. In Direct-S, an (18)O-labeling technique was used to produce internal standards of the targeted peptides, and only targeted peptides were selected for tandem mass spectrometry (MS/MS) fragmentation to increase sensitivity and efficiency. The (16)O/(18)O ion pairs of target peptides and the elution time/fragmental pattern of the internal standards were used to facilitate the identification of the low-abundance peptides. Using Direct-S, three candidate biomarkers, α1-antitrypsin (A1AT), galectin-3 binding protein (LG3BP) and cathepsin D (CTSD), which represent different abundance levels, were quantified in serum samples of colorectal cancer (CRC) patients and healthy candidates. Direct-S exhibited good linearity of response from 20 fmol to 0.5 nmol (r > 0.9845). Reliable quantification across five orders of magnitude and as low as 71 pg μL(-1) was achieved in serum samples. In conclusion, Direct-S is a low cost, convenient and accurate method for verifying serum biomarkers.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c5an00165j | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Efficacy of GABA aminotransferase inactivator OV329 in models of neuropathic and inflammatory pain without tolerance or addiction.
Proc Natl Acad Sci U S A
January 2025
Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405.
Dysregulation of GABAergic inhibition is associated with pathological pain. Consequently, enhancement of GABAergic transmission represents a potential analgesic strategy. However, therapeutic potential of current GABA agonists and modulators is limited by unwanted side effects.
View Article and Find Full Text PDFStructural basis of nearest-neighbor cooperativity in the ring-shaped gene regulatory protein TRAP from protein engineering and cryo-EM.
Proc Natl Acad Sci U S A
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210.
The homo-dodecameric ring-shaped RNA binding attenuation protein (TRAP) from binds up to twelve tryptophan ligands (Trp) and becomes activated to bind a specific sequence in the 5' leader region of the operon mRNA, thereby downregulating biosynthesis of Trp. Thermodynamic measurements of Trp binding have revealed a range of cooperative behavior for different TRAP variants, even if the averaged apparent affinities for Trp have been found to be similar. Proximity between the ligand binding sites, and the ligand-coupled disorder-to-order transition has implicated nearest-neighbor interactions in cooperativity.
View Article and Find Full Text PDFInvestigation of Transformation Pathways of Polyfluoroalkyl Substances during Chlorine Disinfection.
Environ Sci Technol
January 2025
Department of Civil and Environmental Engineering, University of Missouri, Columbia, Missouri 65211, United States.
Recent regulations on perfluorinated compounds in drinking water underscore the need for a deeper understanding of the formation of perfluorinated compounds from polyfluoroalkyl substances during chlorine disinfection. Among the compounds investigated in this study, N-(3-(dimethylaminopropan-1-yl)perfluoro-1-hexanesulfonamide (N-AP-FHxSA) underwent rapid transformation during chlorination. Within an hour, it produced quantitative yields of various poly- and per-fluorinated products, including perfluorohexanoic acid (PFHxA).
View Article and Find Full Text PDFFlap endonuclease 1 repairs DNA-protein cross-links via ADP-ribosylation-dependent mechanisms.
Sci Adv
January 2025
Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, MD 20892, USA.
DNA-protein cross-links (DPCs) are among the most detrimental genomic lesions. They are ubiquitously produced by formaldehyde (FA), and failure to repair FA-induced DPCs blocks chromatin-based processes, leading to neurodegeneration and cancer. The type, structure, and repair of FA-induced DPCs remain largely unknown.
View Article and Find Full Text PDFExperimental-design-based optimization of dispersive liquid-liquid microextraction coupled with gas chromatography-negative-ion chemical ionization-mass spectrometry for the determination of pyrethroids in agricultural products and drinks.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess
January 2025
Department of Chemistry, National Kaohsiung Normal University, Kaohsiung City, Taiwan.
Pyrethroids are synthetic chemicals that account for 16% of the international insecticide market and have been shown to be of varying toxicity to different species. There are various methods available for detecting pyrethroids in agricultural products, but these products must be pre-treated to remove interference from the food matrix, such as through dispersion liquid-liquid microextraction (DLLME). This study employed two experimental design methods to optimize the continuous and discontinuous experimental parameters of DLLME and investigated whether DLLME combined with GC-NICI-MS is effective for detecting pyrethroids in agricultural products.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!