108 articles
Denaturation (biochemistry)
Denaturation in biochemistry is the loss of a protein's or nucleic acid's native structure, caused by heat, pH extremes, or chemical agents, without breaking covalent bonds.
Dimethyl labeling
Dimethyl labeling is a chemical labeling method for quantitative proteomics in which peptide N-termini and lysine amines are reductively dimethylated with formaldehyde isotopologues, comparing protein abundance across two to five samples in one LC-MS experiment.
DNA ladder
A DNA ladder, also called a DNA marker or molecular-weight size marker, is a mixture of DNA fragments of known lengths run on gels to size unknown samples.
DNA nanoswitch
A DNA nanoswitch is a self-assembled DNA construct that loops when it binds a target molecule, enabling biosensing and molecular interaction measurements by gel electrophoresis.
Dot blot
A dot blot is a membrane-based assay in which protein or nucleic acid samples are spotted directly onto a membrane and detected with labeled antibodies or probes.
Edman degradation
Edman degradation is a protein chemistry method that sequentially removes and identifies the N-terminal amino acid of a peptide or protein, one residue per cycle, to determine its sequence.
Ethidium bromide
Ethidium bromide (EtBr), a phenanthridinium fluorescent dye that intercalates between DNA base pairs, is the classical stain for agarose gel electrophoresis; adopted in 1969, it is a mutagen now widely replaced by SYBR Safe, GelRed, and similar dyes.
Far-western blotting
Far-western blotting, also called Far-Western Blot, is a membrane-based molecular biology method derived from the western blot that detects direct protein–protein interactions using a labeled bait protein probe.
Fast protein liquid chromatography
Fast protein liquid chromatography (FPLC) is a preparative liquid chromatography method that separates proteins and other biomolecules in aqueous buffers, introduced by Pharmacia in 1982.
Fehling's solution
Fehling's solution, or Fehling's reagent, is an alkaline copper(II) test for reducing sugars and aliphatic aldehydes, devised by Hermann von Fehling in 1848 to quantify sugar in urine.
Fluorescein
Fluorescein (uranine, fluorescein sodium) is a xanthene dye, C20H12O5, synthesized by Adolf von Baeyer in 1871, absorbing near 490 nm and emitting green fluorescence; used in ophthalmic angiography, FITC antibody labeling, pH probes, and water tracing.
Fluorescence labeling
Fluorescence labeling is a bench biology technique that attaches fluorescent dyes or proteins to biomolecules or cells, letting researchers visualize their presence, localization, and abundance.
Fluorogenic tetrazine probes
Fluorogenic tetrazine probes are bioorthogonal labeling reagents in which a tetrazine quenches an attached fluorophore until it reacts with a dienophile, restoring fluorescence for no-wash live-cell and in vivo imaging.
Fluorophore
Fluorophore: a molecular entity, often organic, that emits fluorescence after absorbing light at a shorter excitation wavelength. Families include organic dyes (FITC, Alexa Fluor), fluorescent proteins (GFP), and quantum dots; used in microscopy, flow cytometry, and FRET.
Giemsa stain
Giemsa stain, a Romanowsky stain developed by Gustav Giemsa in 1904 from azure B and eosin Y, is the WHO-recommended stain for malaria microscopy and chromosome banding, stained at pH 7.2.
H&E stain
H&E stain (hematoxylin and eosin), also called haematoxylin-eosin, is the routine histopathology stain: hematoxylin with a metal mordant colors nuclei blue-purple, eosin colors cytoplasm pink; derived from logwood, established 1875–1878.
Helicase-dependent amplification
Helicase-dependent amplification (HDA) is an isothermal DNA amplification method, reported in 2004, in which a helicase enzyme separates DNA strands, replacing PCR's thermal cycling and suiting point-of-care diagnostics.
HEPES buffer
HEPES buffer is a zwitterionic Good's buffer, introduced by Norman Good and colleagues in 1966, that holds aqueous biological solutions near physiological pH and is widely used in cell culture.
Hydrogen–deuterium exchange mass spectrometry
Hydrogen–deuterium exchange mass spectrometry (HDX-MS) measures the exchange of protein backbone amide hydrogens with deuterium from solvent, using the resulting mass shifts to map protein structure, dynamics, and interactions.
Hydrogen–deuterium exchange measurement
Hydrogen–deuterium exchange measurement (HDX) is a biophysical technique that monitors exchange of protein backbone amide hydrogens with solvent deuterium, most often by mass spectrometry, to characterize protein structure and dynamics.
Immobilized metal affinity chromatography
Immobilized metal affinity chromatography (IMAC) is a protein purification technique separating proteins by affinity for metal ions chelated to a solid support, used mainly to purify His-tagged recombinant proteins in one step.
Immunoaffinity chromatography
Immunoaffinity chromatography (IAC) is a liquid chromatography method in which immobilized antibodies selectively capture and purify a target biomolecule from a complex mixture, first reported in 1963.
In-cell DEER
In-cell DEER is the application of double electron–electron resonance (DEER, also called PELDOR) spectroscopy to measure nanometer-scale distances between two spin labels on a biomolecule inside a living cell, first demonstrated in 2010.
Iodine staining
Iodine staining is a bench histochemical test in which an iodine–iodide solution such as Lugol's colors starch blue-black and glycogen reddish-brown, giving a fast visual readout of these polysaccharides in plant and animal tissues.
Iodoacetamide
Iodoacetamide, or 2-iodoacetamide, is an alkylating reagent with formula C2H4INO that reacts with cysteine thiol groups in proteins, widely used to prevent disulfide re-formation in proteomics sample preparation.
Isobaric labeling
Isobaric labeling is a mass spectrometry method in proteomics that tags peptides from several samples with reagents of identical total mass, so pooled samples are quantified together from reporter ions, with commercial tags reaching 27 samples.
Isobaric tag for relative and absolute quantitation
Isobaric tags for relative and absolute quantitation (iTRAQ) are amine-reactive labels used in mass spectrometry proteomics to quantify proteins across up to eight samples simultaneously.
iTRAQ
iTRAQ (isobaric tags for relative and absolute quantitation) is a proteomics labeling method that quantifies proteins across up to eight samples in one mass spectrometry run.
Label-free quantification
Label-free quantification (LFQ) is a mass spectrometry proteomics method comparing protein abundance across samples by peptide ion intensities or spectral counts, without isotope or chemical labeling.
Lipidomics
Lipidomics is the analysis of lipid composition, structure, and changes in biological samples such as cells, tissues, or body fluids, most often by mass spectrometry and nuclear magnetic resonance spectroscopy.