Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new 6-plex isobaric mass tagging technology is presented, and proof of principle studies are carried out using standard protein mixtures and human cerebrospinal fluid (CSF) samples. The Tandem Mass Tags (TMT) comprise a set of structurally identical tags which label peptides on free amino-terminus and epsilon-amino functions of lysine residues. During MS/MS fragmentation, quantification information is obtained through the losses of the reporter ions. After evaluation of the relative quantification with the 6-plex version of the TMT on a model protein mixture at various concentrations, the quantification of proteins in CSF samples was performed using shotgun methods. Human postmortem (PM) CSF was taken as a model of massive brain injury and comparison was carried out with antemortem (AM) CSF. After immunoaffinity depletion, triplicates of AM and PM CSF pooled samples were reduced, alkylated, digested by trypsin, and labeled, respectively, with the six isobaric variants of the TMT (with reporter ions from m/z = 126.1 to 131.1 Th). The samples were pooled and fractionated by SCX chromatography. After RP-LC separation, peptides were identified and quantified by MS/MS analysis with MALDI TOF/TOF and ESI-Q-TOF. The concentration of 78 identified proteins was shown to be clearly increased in PM CSF samples compared to AM. Some of these proteins, like GFAP, protein S100B, and PARK7, have been previously described as brain damage biomarkers, supporting the PM CSF as a valid model of brain insult. ELISA for these proteins confirmed their elevated concentration in PM CSF. This work demonstrates the validity and robustness of the tandem mass tag (TMT) approach for quantitative MS-based proteomics.
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PMID:Relative quantification of proteins in human cerebrospinal fluids by MS/MS using 6-plex isobaric tags. 1831 1

The human osteosarcoma U2OS cell line is one of the first generated cell lines and is used in various areas of biomedical research. Knowledge of its protein expression is limited and no comprehensive study on the proteome of this cell line has been reported to date. Proteomics technology was used in order to analyse the proteins of the U2OS cell line. Total protein extracts were separated by two-dimensional gel electrophoresis (2-DE) and analysed by matrix-assisted laser desorption ionisation-mass spectrometry (MALDI-MS) and MALDI--MS-MS following in-gel digestion with trypsin and, finally, protein identification was carried out by peptide mass fingerprint (PMF) and post source decay (PSD), respectively. Approximately 3,000 spots were excised from two 2-DE gels and were analysed, resulting in the identification of 237 different gene products. The majority of the identified proteins were enzymes, regulatory proteins and RNA-associated proteins, while leukocyte markers and oncogenes were also present. Our findings include 11 protooncogenes (FKBP4, SRC8, PSD10, FUBP1, PARK7, NPM, PDIA1, OXRP, SET, TCTP and GRP75) related to the cancerous state of the U2OS cell line. The U2OS 2-DE database provides the basis for future protein studies.
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PMID:The proteome profile of the human osteosarcoma U2OS cell line. 1835 81