Chemoproteomic methods for detecting and profiling electrophilic post-translational modifications (PTMs) and oxidative PTMs in proteins are described. The methods including contacting a proteomic mixture with a probe having hydrazine and alkyne moieties or oxyamine and alkyne moieties to form a covalent linkage between the hydrazine or oxyamine moiety of the probe and the electrophilic PTM or oxidative PTM of the protein. The resulting alkyne-derivatized proteins are labelled with an azide modified tag via a click chemistry reaction. The labelled proteins can then be detected or profiled using techniques such as, for example, fluorescence imaging or mass spectrometry. Also described are protein conjugates having a covalent linkage formed by reaction of a hydrazine or oxyamine moiety of a probe with an electrophilic or oxidative PTM of a protein.

Some embodiments disclosed herein provide a plurality of compositions each comprising a protein binding reagent conjugated with an oligonucleotide. The oligonucleotide comprises a unique identifier for the protein binding reagent it is conjugated with, and the protein binding reagent is capable of specifically binding to a protein target. Further disclosed are methods and kits for quantitative analysis of a plurality of protein targets in a sample and for simultaneous quantitative analysis of protein and nucleic acid targets in a sample. Also disclosed herein are systems and methods for preparing a labeled biomolecule reagent, including a labeled biomolecule agent comprising a protein binding reagent conjugated with an oligonucleotide.

The present disclosure provides methods that combine RNA fluorescent in situ sequencing (FISSEQ) with other molecular detection modalities, forming an integrated panomic detection platform. In various embodiments, the present disclosure provides systems and methods to prepare a biological sample to preserve the spatial relationships of biomolecules of interest within the biological sample for FISSEQ detection.

The present invention relates to a method for identifying a target protein using a thermal stability shift-based fluorescence difference in two-dimensional gel electrophoresis, and more specifically, a method for identifying a protein, which is a target of a specific drug, by analyzing, by means of a fluorescence difference in two-dimensional gel electrophoresis, a thermal stability shift in the protein when a specific drug, preferably a bioactive molecule, binds to the target protein.

Methods for peptide and/or protein quantification by mass spectrometry using labeled peptides, wherein multiple labels lead to distinct fragments for the labeled peptides and their unlabeled variant, thus facilitating data analysis and enhancing the potential for quantification. Methods for selecting the label and label position are further given, as well as sets of labeled peptides resulting from or for use in the above-mentioned methods. The methods and substances are especially useful for data-independent or multiplexed parallel reaction monitoring proteomics applications involving peptide quantification.

The present invention relates to methods and compositions for monitoring, diagnosis, prognosis, and determination of treatment regimens in subjects suffering from or suspected of having a renal injury. In particular, the invention relates to using a one or more assays configured to detect a kidney injury marker selected from the group consisting of Cathepsin B, Renin, Dipeptidyl Peptidase IV, Neprilysin, Beta-2-microglobulin, Carbonic anhydrase IX, and C-X-C motif chemokine 2 as diagnostic and prognostic biomarkers in renal injuries.

The present invention generally provides systems and methods for the detection, identification, or characterization of differences between properties or behavior of corresponding species in two or more mixtures comprised of molecules, including biomolecules and/or molecules able to interact with biomolecules, using techniques such as partitioning. The experimental conditions established as distinguishing between the mixtures of the molecules using the systems and methods of the invention can also be used, in some cases, for further fractionation and/or characterization of the biomolecules and/or other molecules, using techniques such as single-step or multiple-step extraction, and/or by liquid-liquid partition chromatography. The methods could also be used for discovering and identifying markers associated with specific diagnostics, and can be used for screening for such markers once discovered and identified during diagnostics screening.

In one aspect, the disclosure provides methods of distinguishing a glycosaminoglycan from one or more other components in a sample by subjecting the sample to size-exclusion chromatography using a mobile phase having a pH of 6.8 or lower. A mobile phase having a pH of 6.8 or lower is found to improve the separation of glycosaminoglycans from proteins during size exclusion chromatography. In some embodiments, improved separation is due to the low pH of the mobile phase causing elution of less dispersed fractions of the protein and/or glycosaminoglycan. In some embodiments, the overlap between protein and/or glycosaminoglycan fractions is reduced.

Methods for preparing labeled glycosylamines from a complex matrix are provided. The methodology includes the steps of: denaturing glycoproteins in a complex matrix to form a denatured complex matrix mixture; loading the denatured complex matrix mixture onto a MWCO filtration device; adding a glycosidase enzymatic solution onto the MWCO filtration device to form a deglycosylated complex matrix mixture comprising glycosylamines; collecting glycosylamines released from the MWCO filtration device; and derivatizing glycosylamines with a rapid tagging reagent to form a plurality of labeled glycosylamines suitable for detection in various liquid chromatography systems and detectors.

Disclosed is a proteomic reactor, comprising a pipette tip, an ion exchange resin filler and a solid-phase extraction membrane. The solid-phase extraction membrane is filled into the lower end of the pipette tip, and the ion exchange resin is filled into the lower end of the pipette tip and is located above the solid-phase extraction membrane. The ion exchange resin is a strong cation exchange resin or a strong anion exchange resin. Disclosed is a protein chromatographic separation platform comprising the proteomic reactor and a liquid chromatography-mass spectrometer. Disclosed is the use of the proteomic reactor and protein chromatographic separation platform in the protein identification and protein quantitative analysis of a cell, a tissue or a blood sample.