Biosynthetic intermediates and stereochemical aspects of aldehyde biosynthesis in the marine diatom Thalassiosira rotula.
Intermediates of the aldehyde biosynthesis in Thalassiosira rotula are investigated. Use of labeled precursors and cell preparations proves production of 2E,4Z-octadienal from 6Z,9Z,12Z-hexadecatrienoic acid (C16:3 omega-4) through the lipoxygenase-dependent intermediate (9S)-9-hydroperoxyhexadeca-6,10,12-trienoic acid. On the contrary, synthesis of 2E,4Z,7Z-decatrienal involves mainly EPA (C20:5 omega-3) by a 11R-lipoxygenase, as suggested by identification of chiral 11R-HEPE (12% e.e.) in the diatom extracts. Consistently with the necessity to have a rapid transport and metabolization of the intermediate hydroperoxides, we show that lipoxygenase and lyase activities are both found in the same subcellular fraction of the microalga.
d'Ippolito
Giuliana
G
Istituto di Chimica Biomolecolare, CNR, Via Campi Flegrei 34, I-80078 Pozzuoli (Napoli), Italy.
Cutignano
Adele
A
Tucci
Sara
S
Romano
Giovanna
G
Cimino
Guido
G
Fontana
Angelo
A
D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D000475:Alkenes / Q000737:chemistry; D017377:Diatoms / Q000737:chemistry* / Q000201:enzymology*; D015118:Eicosapentaenoic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D008084:Lipoxygenase / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism
C508576:2E,4Z,7Z-decatrienal; D000447:Aldehydes; D000475:Alkenes; D005227:Fatty Acids; C474371:2,4-octadienal; D015118:Eicosapentaenoic Acid; D008084:Lipoxygenase