title: Enzymatic desaturation of fatty acids: delta11 desaturase activity on cyclopropane acid probes.
abstract: The formation of methylenecyclopropanes by enzymatic desaturation of 11-cyclopropylundecanoic acid (1) and its disubstituted derivatives cis- and trans-3-5 has been investigated using the Delta(11) desaturase of Spodoptera littoralis as model enzyme. Gas chromatography coupled to mass spectrometry analyses of methanolyzed lipidic extracts from tissues incubated with each probe revealed that all the cyclopropyl fatty acids were transformed into the corresponding 11-cyclopropylidene acids, except for compound trans-5 (5b), which was not desaturated at C11. The formation of methylenecyclopropane 9 as the only reaction product from 1 indicates that a potential radical intermediate is too short-lived to allow rearrangement reactions. Information on the Delta(11) desaturase substrate binding domain is provided considering the cyclopropyl probes 3-5 as conformationally restricted analogues of the straight-chain substrates.
authors.affiliation: Departamento de Química Orgánica Biológica, Instituto de Investigaciones Químicas y Ambientales de Barcelona, Consejo Superior de Investigaciones Científicas, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Villorbina
authors.forename: Lidia
authors.initials: L
authors.lastname: Roura
authors.forename: Francisco
authors.initials: F
authors.lastname: Camps
authors.forename: Jesús
authors.initials: J
authors.lastname: Joglar
authors.forename: Gemma
authors.initials: G
authors.lastname: Fabriàs
mesh_terms: D000818:Animals; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003521:Cyclopropanes / Q000737:chemistry / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D008962:Models, Theoretical; D018411:Spodoptera / Q000201:enzymology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D003521:Cyclopropanes; D005227:Fatty Acids; D007202:Indicators and Reagents; C028775:cyclopropane fatty acids; D044943:Fatty Acid Desaturases