proteomic

Proteomics is the large-scale study of proteomes, the complete set of proteins produced by an organism, tissue, or cell, including their expression, structure, function, and interactions. The proteome is dynamic, varying with development, cell type, disease state, and environmental conditions, making proteomics distinct from genomics. Research in this field seeks to identify which proteins are present, measure their abundance, determine localization, characterize post-translational modifications, and map protein networks.

Mass spectrometry-based techniques form the core of proteomics, often combined with protein or peptide separation methods. In bottom-up proteomics, proteins are digested into peptides and analyzed by LC-MS/MS with database searching to infer proteins. Top-down proteomics analyzes intact proteins to preserve information about isoforms and certain modifications. Other approaches include two-dimensional gel electrophoresis and affinity-based methods. Quantification can be label-based (such as SILAC, iTRAQ, or TMT) or label-free, enabling comparisons across samples. Studying post-translational modifications like phosphorylation, glycosylation, and ubiquitination is a major emphasis.

Data interpretation relies on bioinformatics and databases, including protein sequence and function resources such as UniProt, and structural repositories like the Protein Data Bank. Proteomics also integrates with genomics and transcriptomics in proteogenomics and systems biology to build comprehensive models of biological processes.

Applications span biomarker discovery, drug target identification, pathway analysis, and insights into disease mechanisms, aging, and personalized medicine. Challenges include the wide dynamic range of protein abundance, sample complexity, reproducibility, and the need for standardization in data generation and reporting. The field emerged in the late 20th century and continues to evolve with advances in instrumentation and computational methods. The term proteomic refers to methods, studies, or data related to proteomics.