Epicocconone

Epicocconone is a long Stokes' shift fluorogenic natural product found in the fungus Epicoccum nigrum.^[1] Though weakly fluorescent in water (green emission, 520 nm) it reacts covalently yet reversibly with primary amines such as those in proteins to yield a product with a strong orange-red emission (610 nm).^[2] Epicoconone is notable because it the first covalent/reversible/turn-on fluorophore to be discovered and is a natural product with a new fluorescent scaffold. It is also cell membrane permeable, unlike many other fluorophores, and subsequently can be used in in vivo (live cell) applications.^[2] Additionally, this dye can be used as a sensitive total protein stain for 1D and 2D electrophoresis,^[3] quantitative determination of protein concentration,^[4] making it a powerful loading control for Western blots.^[5]

Epicocconone

Names
Preferred IUPAC name (6S,9aS)-6-(Hydroxymethyl)-3-[(1Z,4E,6E,8E)-1-hydroxy-3-oxodeca-1,4,6,8-tetraen-1-yl]-9a-methyl-5,6-dihydro-2H-furo[3,2-g][2]benzopyran-2,9(9aH)-dione
Other names Deep Purple Lava Purple Lightning Fast
Identifiers
CAS Number	371163-96-1 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:51226
ChemSpider	8398759
PubChem CID	56464320
UNII	6QLH9631R8 Y
InChI InChI=1S/C23H22O7/c1-3-4-5-6-7-8-15(25)11-19(26)20-18-10-14-9-16(12-24)29-13-17(14)21(27)23(18,2)30-22(20)28/h3-8,10-11,13,16,24,26H,9,12H2,1-2H3/b4-3+,6-5+,8-7+,19-11-/t16-,23-/m0/s1 Key: JKMBMIMLVFMXRW-LYYFRFARSA-N InChI=1/C23H22O7/c1-3-4-5-6-7-8-15(25)11-19(26)20-18-10-14-9-16(12-24)29-13-17(14)21(27)23(18,2)30-22(20)28/h3-8,10-11,13,16,24,26H,9,12H2,1-2H3/b4-3+,6-5+,8-7+,19-11-/t16-,23-/m0/s1 Key: JKMBMIMLVFMXRW-LYYFRFARBG
SMILES C/C=C/C=C/C=C/C(=O)/C=C(/C1=C2C=C3C[C@H](OC=C3C(=O)[C@]2(OC1=O)C)CO)\O
Properties
Chemical formula	C23H22O7
Molar mass	410.422 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthetic variant

In addition to the natural variant from the fungus, there are several synthetic analogs.^[6] With respect to protein staining properties there are few differences between natural and synthetic analogs.

Reaction

^[7]