Biosynthesis of 1‐alkenes in higher plants

Abstract

Uneven numbered 1‐alkenes, such as 1‐pentadecene, 1‐heptadecene, 1,8‐heptadecadiene, 1,8,11‐heptadecatriene and 1,8,11,14‐heptadecatetraene are the predominant hydrocarbons in germinating safflower (Carthamus tinctorius L.). According to their chain length and positions of double bonds they are derived from palmitic, stearic, oleic, linoleic or linolenic acid, respectively. This has been proved by administration of synthetic α‐, β‐, or γ‐deuterated 12‐phenyldodecanoic acids to germinating safflower. Mass spectrometric analysis of the resulting deuterium‐labelled 11‐phenyl‐1‐undecenes shows that only a single hydrogen from C‐3 and carbon dioxide from C‐1 of the precursor fatty acid is lost during vinyl group formation. A strong isotope effect (kH/kD≥ 10) during the conversion of racemic 12‐phenyl[3‐2H]dodecanoic acid to 11‐phenyl‐1‐[2‐2H]undecene is consistent with an initial enzymatic attack on a non‐activated hydrogen at C‐3 accompanied by simultaneous fragmentation into the respective 1‐alkene and carbon dioxide. Mechanisms, based on ionic or radical abstraction of a hydrogen from C‐3 of the fatty acid, followed by decarboxylation are discussed. The results are applicable to the formation of various vinylic substituents in natural products such as porphyrins, acetylenic hydrocarbons, pheromones from marine brown algae and terpenoids.

Terminal Olefin (1-Alkene) Biosynthesis by a Novel P450 Fatty Acid Decarboxylase from Jeotgalicoccus Species

“…Terminal olefin (or 1-alkene) production has been reported mainly in eukaryotic organisms (25,39,42). Here, we report that terminal olefin biosynthesis is also common in bacteria of the genus Jeotgalicoccus, a novel genus within the low-GϩC-content Gram-positive firmicutes often associated with sea animals found in seawater (28,55).…”

“…On the other hand, some eukaryotes produce terminal olefins (also referred to as ␣-olefins or 1-alkenes) derived from fatty acid precursors that cannot be explained by any mechanism mentioned above. Examples are 1-pentadecene in beetles of the genus Tribolium (25, 53), 1-heptadecene and related higher unsaturated polyenes in plants such as Carthamus tinctorius (24,42), and C 23 -C 33 dienes and trienes in the green microalga Botryococcus braunii race A (50,51). The last is the only natural organism known to overproduce true hydrocarbons and therefore has been intensively studied in recent years as a source for advanced biofuels from algae (39).…”

Volatile components of Centaurea cineraria L. subsp. umbrosa (Lacaita) Pign. and Centaurea napifolia L. (Asteraceae), two species growing wild in Sicily

“…16,17 The presence of 1-pentadecene (1.6%), identified in this oil, is probably due to the palmitic acid. 18 The content of palmitic acid (20.8%) was also remarkable in the oil of C. cineraria. The absence of important flavour components in both oils accounts for the poor flavour quality of these oils.…”

Volatile Metabolites of Pathogens: A Systematic Review

“…Isoprene is also one of the main volatiles in the breath of mammals and is less applicable as a focus for in vivo studies [25]. 1-undecene [#6] and other less well-studied alkenes [#3–5] are suggested to be produced mainly by PA, and are most likely the product of degradation of fatty acids through the b-oxidation pathway, a pathway that is suggested for most volatile hydrocarbons [15], [26]. 1,3-butadiene [#2] is reported to be produced by gram-positive bacteria, but not by gram-negative bacteria.…”