High-Resolution IMS-MS to Assign Additional Disulfide Bridge Pairing in Complementarity-Determining Regions of an IgG4 Monoclonal Antibody.

Monoclonal antibodies (mAbs) have taken on an increasing importance for the treatment of various diseases, including cancers and immunological disorders. Disulfide bonds play a pivotal role in therapeutic antibody structure and activity relationships. Disulfide connectivity and cysteine-related variants are considered as critical quality attributes that must be monitored during mAb manufacturing and storage, as non-native disulfide bridges and aggregates might be responsible for loss of biological function and immunogenicity.

An ultrasensitive nano UHPLC-ESI-MS/MS method for the quantification of three neuromedin-like peptides in microdialysates.

Aim: An ultrasensitive nano UHPLC-ESI-MS/MS method is developed to simultaneously monitor three low-concentration neuromedin-like peptides in microdialysates.

Results: Peptide preconcentration and sample desalting is performed online on a trap column. A shallow gradient slope at 300 nl/min on the analytical column maintained at 35°C, followed by two saw-tooth column wash cycles, results in the highest sensitivity and the lowest carryover.

Improved sensitivity of the nano ultra-high performance liquid chromatography-tandem mass spectrometric analysis of low-concentrated neuropeptides by reducing aspecific adsorption and optimizing the injection solvent.

Obtaining maximal sensitivity of nano UHPLC-MS/MS methods is primordial to quantify picomolar concentrations of neuropeptides in microdialysis samples. Since aspecific adsorption of peptides to Eppendorf tubes, pipette tips and UHPLC vials is detrimental for method sensitivity, a strategy is presented to reduce adsorption of these peptides during standard preparation. Within this respect, all procedural steps from dissolution of the lyophilized powder until the injection of the sample onto the system are investigated.

Transcription cofactors TRIM24, TRIM28, and TRIM33 associate to form regulatory complexes that suppress murine hepatocellular carcinoma.

TRIM24 (TIF1α), TRIM28 (TIF1β), and TRIM33 (TIF1γ) are three related cofactors belonging to the tripartite motif superfamily that interact with distinct transcription factors. TRIM24 interacts with the liganded retinoic acid (RA) receptor to repress its transcriptional activity. Germ line inactivation of TRIM24 in mice deregulates RA-signaling in hepatocytes leading to the development of hepatocellular carcinoma (HCC).

Proteomic analysis of malignant B-cell derived microparticles reveals CD148 as a potentially useful antigenic biomarker for mantle cell lymphoma diagnosis.

The diagnosis of mature B-cell neoplasms (MBCN) remains difficult in a number of cases, especially leukemic phases of non-Hodgkin lymphoma, for which discriminating criteria or biomarker are often lacking. To identify new surface biomarkers, we developed an original proteomic approach based on mass spectrometry analysis of plasma membrane microparticles derived from chronic B-cell lymphoproliferations of single patients: chronic lymphocytic leukemia (CLL), small cell lymphoma (SLL) and mantle cell lymphoma (MCL). A straightforward selection process for proteomic-based candidate biomarker identification was further constructed in order to propose potentially useful and relevant biomarkers.

Evidence for the formation of a covalent thiosulfinate intermediate with peroxiredoxin in the catalytic mechanism of sulfiredoxin.

The typical 2-Cys peroxiredoxins are thiol-peroxidases involved in the physiology of hydrogen peroxide not only as a toxic but also as a signaling molecule. Coordination of these functions depends on the sulfinylation of the catalytic Cys, a modification reversed by ATP-dependent sulfiredoxin, which specifically reduces the sulfinic acid group of overoxidized 2-Cys peroxiredoxins into a sulfenic acid. Sulfiredoxin was originally proposed to operate by covalent catalysis, with formation of a peroxiredoxin-sulfiredoxin intermediate linked by a thiosulfinate bond between the catalytic Cys of both partners, a hypothesis rejected by a study of the human enzyme.