''Graphium sarpedon'' which contains pterobilin Pterobilin is a blue

bile pigment Bilins, bilanes or bile pigments are biological pigments formed in many organisms as a metabolic product of certain porphyrins. Bilin (also called bilichrome) was named as a bile pigment of mammals, but can also be found in lower vertebrates, inve ...

found in ''

Nessaea ''Nessaea'' is a genus of nymphalid butterflies found in the Neotropical realm. Unlike virtually all other butterflies with blue coloration, the blue colors in this genus are due to pigmentation terobilin (biliverdin IXγ)ref>Doug Taron"It's all ...

'' spp., ''

Graphium agamemnon ''Graphium agamemnon'', the tailed jay, is a predominantly green and black tropical butterfly that belongs to the swallowtail family. The butterfly is also called the green-spotted triangle, tailed green jay, or green triangle. It is a common, n ...

'', '' G. antiphates'', '' G. doson'', and '' G. sarpedon''. It is one of only a few blue pigments found in any animal species, as most animals use

iridescence Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...

to create blue coloration. Other blue pigments of animal origin include phorcabilin, used by other butterflies in '' Graphium'' and ''

Papilio ''Papilio'' is a genus in the swallowtail butterfly family, Papilionidae, as well as the only representative of the tribe Papilionini. The word ''papilio'' is Latin for butterfly. It includes the common yellow swallowtail (''Papilio machaon''), ...

'' (specifically '' P. phorcas'' and '' P. weiskei''), and sarpedobilin, which is used by ''

Graphium sarpedon ''Graphium sarpedon'', the common bluebottle or blue triangle in Australia, is a species of swallowtail butterfly that is found in South and Southeast Asia, as well as eastern Australia. There are approximately sixteen subspecies with diffe ...

''.

Synthetic pathways

Pterobilin 1 is a

chemical precursor In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry, the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway, ...

to sarpedobilin 3 in the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e of the fourth

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

of ''G. sarpedon'' through a double

cyclisation A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where al ...

of the central

vinyl group In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound contain ...

s of the adjacent nitrogens. In the butterfly species ''

Pieris brassicae ''Pieris brassicae'', the large white, also called cabbage butterfly, cabbage white, cabbage moth (erroneously), or in India the large cabbage white, is a butterfly in the family Pieridae. It is a close relative of the small white, ''Pieris ra ...

'', it is produced starting with

acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

and then proceeding to

glycin Glycin, or N-(4-hydroxyphenyl)glycine, is N-substituted p-aminophenol. It is a photographic developing agent used in classic black-and-white developer solutions. It is unrelated to the amino acid glycine. It is typically characterized as thin pl ...

, then

δ-aminolevulinic acid δ-Aminolevulinic acid (also dALA, δ-ALA, 5ALA or 5-aminolevulinic acid), an endogenous non-proteinogenic amino acid, is the first compound in the porphyrin synthesis pathway, the pathway that leads to heme in mammals, as well as chlorophyll in p ...

, then

coproporphyrinogen III Coproporphyrinogen III is a metabolic intermediate in the biosynthesis of many compounds that are critical for living organisms, such as hemoglobin and chlorophyll. It is a colorless solid. The compound is a porphyrinogen, a class of compounds ch ...

, to

protoporphyrin IX Protoporphyrin IX is an organic compound, classified as a porphyrin, that plays an important role in living organisms as a precursor to other critical compounds like heme (hemoglobin) and chlorophyll. It is a deeply colored solid that is not sol ...

and finally into pterobilin. Pterobilin 1 can be

phototransform A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...

ed into Pterobilin 2 and 3 ''in vitro''. Pterobilin 1 can also be thermally rearranged ''in vitro'' into phorcabilin 2.

Biochemical roles

Pterobilin in ''P. brassicae'' is thought to play a role in

photoreception A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiatio ...

for the different instars for metering

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

. In adult ''P. brassicae'' butterflies the compound is thought to have a role in

heat transfer Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...

,Allyn, A. C., Barbier, Michel, Bois-Choussy, Michèle, and Rothschild, M. (1981). Antenna, Londres, 29-31. as the

wing scale Scales are present on the bodies of various insects. A notable example are Lepidoptera, the insect order comprising moths and butterflies, which has scales on their wings and also on the head, parts of the thorax and abdomen as well as parts of the ...

s where pterobilin accumulates differ morphologically in a way that would facilitate photoreception.

References

{{Subject bar, d=Q83373553 Graphium (butterfly) Biological pigments Biblidinae

Synthetic pathways

Biochemical roles

See also

References