title: C31-C34 methylated squalenes from a Bolivian strain of Botryococcus braunii.
abstract: Three new triterpenes, synthesized by a Bolivian strain of the green microalga Botryococcus braunii, were isolated and their chemical structures determined by 1D and 2D NMR, and mass spectrometry. These compounds are tri-, di-, and mono-methylsqualenes, co-occurring with the previously identified tetramethylsqualene and some C(30)-C(32) botryococcenes. In this strain, methylated squalenes constitute up to 24% of the total hydrocarbons and 4.5% of the dry biomass. The results of a pulse-chase experiment with L-[Me-(13)C] methionine provide evidence for the origin of these compounds via methylation of squalene at positions 3, 7, 18 and 22.
authors.affiliation: Laboratoire de Chimie Bioorganique et Organique Physique, Universite Pierre et Marie Curie, Ecole Nationale Supérieure de Chimie de Paris, UMR CNRS 7573, ENSCP, 11 Rue P. et M. Curie, 75231 Paris cedex 05, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Achitouv
authors.forename: Pierre
authors.initials: P
authors.lastname: Metzger
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Rager
authors.forename: Claude
authors.initials: C
authors.lastname: Largeau
mesh_terms: D001838:Bolivia; D000460:Chlorophyta / Q000737:chemistry*; D002849:Chromatography, Gas; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D013185:Squalene / Q000031:analogs & derivatives* / Q000737:chemistry; D014315:Triterpenes / Q000737:chemistry
chemical_list: D014315:Triterpenes; C495560:dimethylsqualene; C495561:mono-methylsqualene; C495562:tetramethylsqualene; C495559:trimethylsqualene; D013185:Squalene