Compounds comprising an isobaric region, an enrichment handle, and a thiol-reactive group are generally described. Methods of using the same (e.g., performing multiplexed quantitative analysis of the reactivity of one or more cysteine residues across multiple samples simultaneously) are also described.

A method for analyzing macromolecules, including peptides, polypeptides, and proteins, employing nucleic acid encoding is disclosed.

A method for analyzing macromolecules, including peptides, polypeptides, and proteins, employing nucleic acid encoding is disclosed.

Bead-based assays for measuring protein biomarkers of proteolytic activity in biological systems are disclosed. In an embodiment, an assay involves incubating a sample containing multiple fragments of a naturally occurring protein with a bead array and subsequently analyzing individual reactive sites of the bead array by mass spectrometry.

Methods for proteomic screening on random protein-bead arrays by mass spec is described. Photocleavable mass tags are utilized to code a protein library (bait molecules) displayed on beads randomly arrayed in an array substrate. A library of probes (prey) can be mixed with the protein-bead array to query the array. Because mass spec can detect multiple mass tags, it is possible to rapidly identify all of the interactions resulting from this mixing.

The present application relates, in general, to compositions comprising anti-TSLP antibody tezepelumab and derivatives thereof having antibody quality attributes.

High-throughput methods for screening large populations of variant proteins are provided. The methods utilize large-scale arrays of microcapillaries, where each microcapillary comprises a solution containing a variant protein, an immobilized target molecule, and a reporter element. Immobilized target molecules may include any molecule of interest, including proteins, nucleic acids, carbohydrates, and other biomolecules. The association of a variant protein with a molecular target is assessed by measuring a signal from the reporter element. The contents of microcapillaries identified in the assays as containing variant proteins of interest can be isolated, and cells expressing the variant proteins of interest can be characterized. Also provided are systems for performing the disclosed screening methods.

The present invention provides a cell-based assay for identifying and/or quantifying anti-CD3 homodimers in a composition comprising a T cell-dependent Bispecific antibody (TDB). In some aspects, the invention T cells comprising a T cell activation responsive reporter are contacted with the TDB to detect the presence of anti-CD3 homodimers. Compositions of reporter T cells and kits are also contemplated.

The present application provides methods and systems to identify host cell protein (HCP) impurities in a sample containing high-abundance proteins. The HCP impurities can be enriched using interacting peptide ligands which have been attached to solid support. The HCP impurities can be eluted from the solid support using solution containing phase transfer surfactants. The isolated HCP impurities can be digested to generate components of the isolated HCP impurities which can subsequently be identified using a mass spectrometer.

The present disclosure relates to chimeric ABC transporter proteins and methods of screening for molecules that bind to the periplasmic, extracellular, and/or luminal face of an ABC transporter protein using the chimeric ABC transporters. For example, in some embodiments, screening methods involve providing a chimeric ABC transporter in which one or more regions of the periplasmic, extracellular, and/or luminal face of the ABC transporter are substituted with one or more equivalent regions of the periplasmic, extracellular, and/or luminal face of a different ABC transporter and selecting for molecules that bind to the ABC transporter but do not bind to the chimeric ABC transporter. The disclosure also relates to molecules that bind to the periplasmic, extracellular, and/or luminal face of an ABC transporter protein, for example, identified in such screens.