Digoxigenin

Digoxigenin

Names
IUPAC name 3β,12β,14-Trihydroxy-5β-card-20(22)-enolide
Systematic IUPAC name 4-[(1R,3aS,3bR,5aR,7S,9aS,9bS,11R,11aS)-3a,7,11-Trihydroxy-9a,11a-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-1-yl]furan-2(5H)-one
Identifiers
CAS Number	1672-46-4  Y
ChEBI	CHEBI:42098  Y
ChEMBL	ChEMBL1153  Y
ChemSpider	14728  Y
ECHA InfoCard	100.015.279
PubChem CID	15478
UNII	NQ1SX9LNAU  Y
CompTox Dashboard (EPA)	DTXSID6051778
InChI InChI=1S/C23H34O5/c1-21-7-5-15(24)10-14(21)3-4-17-18(21)11-19(25)22(2)16(6-8-23(17,22)27)13-9-20(26)28-12-13/h9,14-19,24-25,27H,3-8,10-12H2,1-2H3/t14-,15+,16-,17-,18+,19-,21+,22+,23+/m1/s1 Y Key: SHIBSTMRCDJXLN-KCZCNTNESA-N Y InChI=1/C23H34O5/c1-21-7-5-15(24)10-14(21)3-4-17-18(21)11-19(25)22(2)16(6-8-23(17,22)27)13-9-20(26)28-12-13/h9,14-19,24-25,27H,3-8,10-12H2,1-2H3/t14-,15+,16-,17-,18+,19-,21+,22+,23+/m1/s1 Key: SHIBSTMRCDJXLN-KCZCNTNEBN
Properties
Chemical formula	C23H34O5
Molar mass	390.51 g/mol
log P	2.57510 [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y  verify  (what is  YN ?) Infobox references

Digoxigenin (DIG) is a steroid found exclusively in the flowers and leaves of the plants Digitalis purpurea , Digitalis orientalis ^{[ disambiguation needed ]} and Digitalis lanata (foxgloves), where it is attached to sugars, to form the glycosides (e.g. digoxin, lanatoside C). ^[2]

Uses in biotechnology

Digoxigenin is a hapten, a small molecule with high antigenicity, that is used in many molecular biology applications similarly to other popular haptens such as 2,4-Dinitrophenol, biotin, and fluorescein. Typically, digoxigenin is introduced chemically (conjugation) into biomolecules (proteins, nucleic acids) to be detected in further assays. K_d of the digoxigenin-antibody interaction has been estimated at ~12 nM ^[3] (compare to K_d~0.1pM for the biotin-streptavidin interaction ^[4] ).

DIG-binding proteins

Tinberg et al. designed artificial proteins that bind DIG. Their best binder, DIG10.3, was a 141 amino acid protein that bound DIG with a dissociation constant (K_d) of 541 (+/- 193) pM. ^[5]

Anti-digoxigenin antibodies with high affinities and specificity are used in a variety of biological immuno-assays (e.g. ELISA). The antibodies are labeled with dyes, enzymes or fluorescence, directly or secondarily, for visualization and detection.

Digoxigenin is thus an all-purpose immuno-tag, and in particular a standard immunohistochemical marker for in situ hybridization. ^{[6] [7]} In this case it is conjugated to a single species of RNA nucleoside triphosphate (typically uridine), which is then incorporated into RNA (a "riboprobe") as it is synthesized by the cellular machinery.

It allows to make :

• sensitive non-radioactive in situ hybridization probes to detect nucleic acids in plants, able to detect 1 μg of plasmid DNA. ^[8]
• peptide-DIG conjugates, i.e. bradykinin assay by very sensitive chemiluminescence immunoassays. ^[9]
• fluorescent and DIG-labeled tracers for competitive immunoassays, i.e. to limit detect digoxin, a drug used to cure cardiac arrhythmia, down to 0.2 ng mL⁻¹. ^[10]
• Digoxigenin may be conjugated to sugars to study glycosylation events, ^[11] even in biological systems.

See also

• Immunostaining

References

1. "Digoxigenin". Material Data Safety Sheet. ChemSrc.
2. Polya G (2003). Biochemical Targets of Plant Bioactive Compounds. New York: CRC Press. ISBN   978-0-415-30829-8.
3. Tetin SY, Matayoshi ED (August 2002). "Measuring antibody affinity and performing immunoassay at the single molecule level". Analytical Biochemistry. 307 (1): 84–91. doi:10.1016/S0003-2697(02)00011-8. PMID   12137783.
4. Duan X (2012). "Quantification of the affinities and kinetics of protein interactions using silicon nanowire biosensors". Nature Nanotechnology. 7 (6): 401–407. Bibcode:2012NatNa...7..401D. doi:10.1038/nnano.2012.82. PMC   4180882 . PMID   22635097.
5. Tinberg CE, Khare SD, Dou J, Doyle L, Nelson JW, Schena A, Jankowski W, Kalodimos CG, Johnsson K, Stoddard BL, Baker D (September 2013). "Computational design of ligand-binding proteins with high affinity and selectivity". Nature. 501 (7466): 212–216. Bibcode:2013Natur.501..212T. doi:10.1038/nature12443. PMC   3898436 . PMID   24005320.
6. Eisel D, Grünewald-Janho S, Krushen B, eds. (2002). DIG Application Manual for Nonradioactive in situ Hybridization (3rd ed.). Penzberg: Roche Diagnostics.
7. Hauptmann G, Gerster T (August 1994). "Two-color whole-mount in situ hybridization to vertebrate and Drosophila embryos". Trends in Genetics. 10 (8): 266. doi:10.1016/0168-9525(90)90008-T. PMID   7940754.
8. Hart SM, Basu C (April 2009). "Optimization of a digoxigenin-based immunoassay system for gene detection in Arabidopsis thaliana". Journal of Biomolecular Techniques. 20 (2): 96–100. PMC   2685603 . PMID   19503620.
9. Décarie A, Drapeau G, Closset J, Couture R, Adam A (1994). "Development of digoxigenin-labeled peptide: application to chemiluminoenzyme immunoassay of bradykinin in inflamed tissues". Peptides. 15 (3): 511–8. doi:10.1016/0196-9781(94)90214-3. PMID   7937327. S2CID   19210640.
10. Mayilo S, Ehlers B, Wunderlich M, Klar TA, Josel HP, Heindl D, Nichtl A, Kürzinger K, Feldmann J (July 2009). "Competitive homogeneous digoxigenin immunoassay based on fluorescence quenching by gold nanoparticles". Analytica Chimica Acta. 646 (1–2): 119–22. Bibcode:2009AcAC..646..119M. doi:10.1016/j.aca.2009.05.023. PMID   19523564.
11. Goodarzi MT, Rafiq M, Turner G (May 1995). "An improved multiwell immunoassay using digoxigenin-labelled lectins to study the glycosylation of purified glycoproteins". Biochemical Society Transactions. 23 (2): 168S. doi:10.1042/bst023168s. PMID   7672194.