108 articles
Luminol
Luminol (5-amino-2,3-dihydro-1,4-phthalazinedione) is a chemiluminescent reagent that glows blue when oxidized in alkali with a catalyst; used in forensic blood detection since Specht 1937 and in clinical immunoassays.
Lysine chemoproteomics
Lysine chemoproteomics is a set of chemical proteomic methods that use lysine-reactive probes and quantitative mass spectrometry to identify reactive, ligandable lysine residues across entire proteomes.
Lysis buffer
Lysis buffer: buffered detergent solution (RIPA, NP-40, urea, RBC lysis) used to break open cells and solubilize proteins; composition, detergent strength, and inhibitors are matched to the target protein and downstream assay.
MOF-based luminescent sensors
MOF-based luminescent sensors are chemical and biological sensors in which a porous metal–organic framework changes its light emission when it encounters a target analyte, detecting ions, molecules, and gases.
nanoPOTS
nanoPOTS (Nanodroplet Processing in One pot for Trace Samples) is a nanoliter-scale sample preparation method for proteomics, introduced in 2018 for single cells and tiny tissue samples.
Native mass spectrometry
Native mass spectrometry is a mass spectrometry method that ionizes proteins and biomolecules under gentle electrospray conditions so noncovalent complexes survive into the gas phase and can be weighed intact.
NBD-Cl
NBD-Cl (4-chloro-7-nitrobenzofurazan, also NBD chloride) is a non-fluorescent benzofurazan reagent that reacts with amines, thiols, and phenols to form fluorescent derivatives used in chromatographic and biochemical analysis.
Nucleic acid quantitation
Nucleic acid quantitation measures DNA or RNA concentration and purity, mainly by UV absorbance at 260 nm (NanoDrop, DeNovix) or by specific fluorescent dyes (Qubit, PicoGreen), which differ in sensitivity and accuracy.
Paramagnetic relaxation enhancement
Paramagnetic relaxation enhancement is an NMR technique in which a paramagnetic center attached to a biomolecule increases nuclear relaxation rates, reporting distances up to roughly 35 Å and detecting sparsely populated conformational states.
Peptide mapping
Peptide mapping is an analytical biochemistry method that digests a protein with a protease and separates the peptides, giving a reproducible fingerprint used to confirm protein identity.
Peptide mass fingerprinting
Peptide mass fingerprinting (PMF) identifies an unknown protein by digesting it into peptides, measuring their masses by mass spectrometry, and matching them against a database.
Periodic acid–Schiff stain
Periodic acid–Schiff (PAS) stain, also called PAS reaction, a histochemical method introduced by McManus in 1946 that oxidizes tissue carbohydrates to aldehydes and stains glycogen, neutral mucins, basement membranes, and fungi pink-magenta with Schiff's reagent.
Phenolphthalein
Phenolphthalein (C20H14O4, CAS 77-09-8) is an acid-base indicator, colorless below pH 8.2 and pink above, synthesized by Baeyer in 1871; formerly a top-selling laxative, withdrawn in 1999 and classified IARC Group 2B.
Phosphate-buffered saline
Phosphate-buffered saline (PBS) is a pH 7.4 salt solution of NaCl, KCl, and phosphate salts used to wash cells and tissue and dilute reagents; standard 1X mix is 137 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2PO4.
Polymer dot
A polymer dot (Pdot) is a fluorescent nanoparticle of semiconducting polymer, smaller than about 30 nm, used as an imaging probe and biosensor in biology and medicine.
Protein staining
Protein staining is a bench technique using dyes or reagents to make proteins visible after separation in gels or on membranes, producing bands used for detection and quantification.
Proteomics
Proteomics, the large-scale study of proteins, also called proteome analysis; complementary to genomics and transcriptomics; dominated by bottom-up LC-MS/MS peptide analysis, with top-down intact-protein, single-cell, and spatial methods emerging.
Pulse SILAC
Pulse SILAC, also known as pulsed or dynamic SILAC, is a quantitative proteomics method that measures new protein synthesis and degradation by briefly switching cells to heavy isotope-labeled amino acids.
qPCR analysis
qPCR analysis, or quantitative PCR, quantifies nucleic acids by monitoring fluorescence in real time as amplification proceeds, converting the threshold cycle into relative expression levels or absolute copy numbers.
Quenching (fluorescence)
Quenching (fluorescence): deactivation of an excited fluorophore by a quencher, via dynamic (collisional, lifetime-shortening) or static (ground-state complex) mechanisms, quantified by the 1919 Stern–Volmer equation and used widely in fluorescent sensing.
Resazurin
Resazurin, sold under the name Alamar Blue, is a blue redox dye that living cells reduce to the fluorescent pink compound resorufin, a conversion used to measure cell viability.
Reverse transcription recombinase polymerase amplification
Reverse transcription recombinase polymerase amplification (RT-RPA) is an isothermal nucleic acid amplification method that converts RNA to cDNA and amplifies it at a constant 37–42 °C.
Rhodamine 123
Rhodamine 123 is a cell-permeant, cationic fluorescent dye of the rhodamine family that accumulates in mitochondria of living cells, used to measure mitochondrial membrane potential and ABCB1 efflux activity.
Secretomics
Secretomics is the mass-spectrometry-based, unbiased identification and quantification of proteins released by a cell, tissue, or organism, with the human secretome estimated at 2,641 genes.
Shotgun lipidomics
Shotgun lipidomics is a mass spectrometry method that infuses a total lipid extract directly into an electrospray source, without chromatography, quantifying hundreds to thousands of lipid species.
Shotgun proteomics
Shotgun proteomics, also called bottom-up proteomics, is a mass spectrometry method that digests proteins into peptides, separates them by LC-MS/MS, and infers the original proteins computationally.
SILAC
SILAC (stable isotope labeling by amino acids in cell culture) is a metabolic labeling method for quantitative mass spectrometry proteomics, reported by Shao-En Ong and colleagues in 2002.
Spectral counting
Spectral counting is a label-free quantification method in shotgun proteomics that estimates relative protein abundance by counting identified tandem mass spectra, formalized in 2004 by Liu, Sadygov, and Yates.
Spectral library search
Spectral library search is a proteomics method that identifies peptides by matching experimental MS/MS spectra against a reference library, hundreds of times faster than sequence database search.
Spin labeling
Spin labeling is a biochemical technique that attaches a stable paramagnetic group, usually a nitroxide radical, to a biomolecule so EPR spectroscopy can report its structure and dynamics.