Torulene (3',4'-didehydro-β,γ-carotene) is a carotene (a hydrocarbon carotenoid) which is notable for being synthesized by red pea aphids (Acyrthosiphon pisum), imparting the natural red color to the aphids, which aids in their camouflage and escape from predation. The aphids have gained the ability to synthesize torulene by horizontal gene transfer of a number of genes for carotenoid synthesis, apparently from fungi.^[1] Plants, fungi, and microorganisms can synthesize carotenoids, but torulene made by pea aphids is the only carotenoid known to be synthesized by an organism in the animal kingdom.^[2]

Torulene

Names
IUPAC name 3′,4′-Didehydro-β,ψ-carotene
Systematic IUPAC name 2-[(1E,3E,5E,7E,9E,11E,13E,15E,17E,19E,21E)-3,7,12,16,20,24-Hexamethylpentacosa-1,3,5,7,9,11,13,15,17,19,21,23-dodecaen-1-yl]-1,3,3-trimethylcyclohex-1-ene
Identifiers
CAS Number	547-23-9 Y
3D model (JSmol)	Interactive image
ChemSpider	4444665
PubChem CID	5281253
UNII	7KKR9CWX9P Y
InChI InChI=1S/C40H54/c1-32(2)18-13-21-35(5)24-15-26-36(6)25-14-22-33(3)19-11-12-20-34(4)23-16-27-37(7)29-30-39-38(8)28-17-31-40(39,9)10/h11-16,18-27,29-30H,17,28,31H2,1-10H3/b12-11+,21-13+,22-14+,23-16+,26-15+,30-29+,33-19+,34-20+,35-24+,36-25+,37-27+ Key: AIBOHNYYKWYQMM-MXBSLTGDSA-N
SMILES C(/C1=C(/CCCC1(C)C)C)=C\C(=C\C=C\C(=C\C=C\C=C(\C=C\C=C(\C=C\C=C(\C=C\C=C(/C)C)C)C)C)C)C
Properties
Chemical formula	C40H54
Molar mass	534.857
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references