Premium
Conversion of 18∶3 Δ9 cis , 12 cis , 15 trans in rat liver microsomes
Author(s) -
Chardigny JeanMichel,
Blond JeanPaul,
Bretillon Lionel,
Mager Estelle,
Poullain Didier,
Martine Lucy,
Vatèle JeanMichel,
Noël JeanPierre,
Sébédio JeanLouis
Publication year - 1997
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-997-0093-1
Subject(s) - microsome , polyunsaturated fatty acid , docosahexaenoic acid , substrate (aquarium) , stereochemistry , eicosapentaenoic acid , chemistry , cis–trans isomerism , in vivo , clinical chemistry , linolenic acid , biochemistry , enzyme , linoleic acid , fatty acid , biology , ecology , microbiology and biotechnology
Several years ago, it was established that the Δ15 trans isomer of α‐linolenic acid is converted in vivo into fatty acids containing 20 and 22 carbons (geometrical isomers of eicosapentaenoic and docosahexaenoic acids). The present study focused on the in vitro Δ6 desaturation, the first step of the biosynthesis of the n‐3 long‐chain polyunsaturated fatty acids from 18:3n‐3. For that purpose, rat liver microsomes were prepared and incubated with radiolabeled 18∶3 Δ9 cis , 12 cis , 15 cis (18∶3 c,c,c ) or 18∶3 Δ9 cis , 12 cis , 15 trans (18∶3 c,c,t ) under desaturation conditions. The data show that 18∶3 c,c,t is converted at a lower rate compared with α‐linolenic acid. The product of conversion of 18∶3 c,c,t may be 18∶4 Δ6 cis , 9 cis , 12 cis , 15 trans resulting from a Δ6 desaturation of the trans substrate. Moreover, the conversion of radiolabeled 18∶3 c,c,t was strongly decreased by the presence of 18∶3 c,c,c (up to 48%) while the 18∶3 c,c,t only slightly decreased the conversion of radiolabeled 18∶3 c,c,c . Thus, the desaturation enzyme presented a higher affinity for the native all‐ cis n‐3 substrate.