Stenusin is a

piperidine Piperidine is an organic compound with the molecular formula (CH2)5NH. This heterocyclic amine consists of a six-membered ring containing five methylene bridges (–CH2–) and one amine bridge (–NH–). It is a colorless liquid with an odor de ...

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

molecule synthesized by

rove beetle The rove beetles are a family (biology), family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave more than half of their abdominal segments exposed. With over 66,000 species in thousand ...

s of the genus ''

Stenus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genera in the kingdom Animalia, with some 3100 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

''. By lowering its abdomen and releasing stenusin, this genus of rove beetle are able to quickly escape predators through a process called skimming.Lusebrink, Inka; Dettner, Konrad; Seifert, Karlheinz. Biosynthesis of Stenusine. ''Journal of Natural Products''. 2008, 71 (5), 743-745. doi:10.1021/np070310w Skimming is caused by the low surface tension of stenusin, which rapidly spreads over water surfaces when emitted and allows the beetle to glide away from danger.Lusebrink, Inka; Dettner, Konrad; Seifert, Karlheinz. Stenusine, an antimicrobial agent in the rove beetle genus Stenus (Coleoptera, Staphylinidae). ''Naturwissenschaften''. 2008, 95, 751-755.

Biosynthesis

Stenusin is biosynthesized in the

pygidial The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is composed o ...

glands of Stenus Latreille, located in the last three segments of the beetles' abdomen. This molecule is the enzymatic product of several reactions that utilize L-lysine, L-isoleucine, and an

acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetallic, or radical base). "Acetate" also describes the conjugate base or ion (specifically, the negatively charged ion called ...

source. First, both L-lysine and L-isoleucine undergo separate

decarboxylation Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is ...

reactions followed by

oxidative deamination Oxidative deamination is a form of deamination that generates α-keto acids and other oxidized products from amine-containing compounds, and occurs primarily in the liver. Oxidative deamination is stereospecific, meaning it contains different ster ...

. The product created from L-lysine undergoes intramolecular

Schiff base In organic chemistry, a Schiff base (named after Hugo Schiff) is a compound with the general structure ( = alkyl or aryl, but not hydrogen). They can be considered a sub-class of imines, being either secondary ketimines or secondary aldim ...

formation to create the piperidine ring found in stenusin. The two amino acid products then combine through a

Stork enamine alkylation The Stork enamine alkylation involves the addition of an enamine to a Michael acceptor (e.g., an α,β -unsaturated carbonyl compound) or another electrophilic alkylation reagent to give an alkylated iminium product, which is hydrolyzed by dilut ...

reaction and are further acylated and reduced to form stenusin. Stenusin Biosynthesis

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References

Piperidine alkaloids