Unusual pattern of fatty acid biosynthesis. Evidence for C-19 desaturase activity in freshwater sponges.
The two long chain fatty acids common in marine demosponges, (5Z, 9Z)-5,9-hexacosadienoic (delta 5,9-26:2) and (5Z, 9Z, 19Z)-5,9,19-hexacosatrienoic (delta 5,9,19-26:3) acids), were identified also as the major phospholipid components in the freshwater sponge Ephydatia fluviatilis. Whereas the typical marine sponge Microciona prolifera biosynthesizes the delta 5,9,19-26:3 acid solely by homologation of exogenous palmitoleic acid (delta 9-16:1) and subsequent desaturation at positions 5 and 9, it was found that the freshwater sponge could further desaturate the delta 5,9-26:2 acid to the triene, indicating for the first time the existence of delta 19 -desaturase activity in a living organism.
Hahn
S
S
Department of Chemistry, Stanford University, California 94305.
Lam
W K
WK
Wu
I
I
Silva
C J
CJ
Djerassi
C
C
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis* / Q000302:isolation & purification; D005618:Fresh Water; D010743:Phospholipids / Q000302:isolation & purification; D011161:Porifera / Q000201:enzymology*
D005227:Fatty Acids; D010743:Phospholipids; D044943:Fatty Acid Desaturases