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Biosynthesis of eicosapentaenoic acid in the microalga Porphyridium cruentum . I: The use of externally supplied fatty acids
Author(s) -
Shiran Devora,
Khozin Inna,
Heimer Yair M.,
Cohen Zvi
Publication year - 1996
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/bf02587913
Subject(s) - eicosapentaenoic acid , biosynthesis , biochemistry , lipidology , metabolic pathway , fatty acid , clinical chemistry , biology , enzyme , polyunsaturated fatty acid , chemistry
The biosynthetic pathways of eicosapentaenoic acid (20:5n‐3) in microalgae, in general, and in Porphyridium cruentum , in particular, are not known. Some of the putative intermediates along the suggested pathways could not be detected probably due to their low endogenous level. In order to increase the endogenous levels of the intermediates, we provided various fatty acids in the growth medium. Exogenously supplied fatty acids were indeed incorporated into algal lipids and were further metabolized along the n‐6 and n‐3 pathways. In the n‐6 pathway, 18:2 was desaturated to 18:3n‐6, elongated to 20:3n‐6, and subsequently desaturated to 20:4n‐6 and then to 20:5n‐3. In the n‐3 pathway, 18:2 was first desaturated to 18:3n‐3 which was then sequentially converted, apparently by the same enzymatic sequence of the n‐6 pathway to 18:4n‐3, 20:4n‐3, and 20:5n‐3.