Mass spectra of acetylenic fatty acid methyl esters and derivatives

Lipids ◽  
1976 ◽  
Vol 11 (8) ◽  
pp. 599-603 ◽  
Author(s):  
R. Kleiman ◽  
M. B. Bohannon ◽  
F. D. Gunstone ◽  
J. A. Barve
Keyword(s):  
Fatty Acid ◽  
Mass Spectra ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Acid Methyl ◽  
Acetylenic Fatty Acid

scholarly journals Novel fatty acid methyl esters from the actinomyceteMicromonospora aurantiaca

2011 ◽  
Vol 7 ◽  
pp. 1697-1712 ◽  
Author(s):  
Jeroen S Dickschat ◽  
Hilke Bruns ◽  
Ramona Riclea
Keyword(s):  
Fatty Acid ◽  
Mass Spectra ◽  
Fatty Acid Methyl Esters ◽  
Fatty Acid Synthase ◽  
Methyl Esters ◽  
Sodium Propionate ◽  
Feeding Experiments ◽  
Acid Methyl ◽  
Adenosyl Methionine ◽  
Branched Compound

The volatiles released byMicromonospora aurantiacawere collected by means of a closed-loop stripping apparatus (CLSA) and analysed by GC–MS. The headspace extracts contained more than 90 compounds from different classes. Fatty acid methyl esters (FAMEs) comprised the major compound class including saturated unbranched, monomethyl and dimethyl branched FAMEs in diverse structural variants: Unbranched, α-branched, γ-branched, (ω−1)-branched, (ω−2)-branched, α- and (ω−1)-branched, γ- and (ω−1)-branched, γ- and (ω−2)-branched, and γ- and (ω−3)-branched FAMEs. FAMEs of the last three types have not been described from natural sources before. The structures for all FAMEs have been suggested based on their mass spectra and on a retention index increment system and verified by the synthesis of key reference compounds. In addition, the structures of two FAMEs, methyl 4,8-dimethyldodecanoate and the ethyl-branched compound methyl 8-ethyl-4-methyldodecanoate were deduced from their mass spectra. Feeding experiments with isotopically labelled [2H10]leucine, [2H10]isoleucine, [2H8]valine, [2H5]sodium propionate, and [methyl-2H3]methionine demonstrated that the responsible fatty acid synthase (FAS) can use different branched and unbranched starter units and is able to incorporate methylmalonyl-CoA elongation units for internal methyl branches in various chain positions, while the methyl ester function is derived fromS-adenosyl methionine (SAM).

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