The synthesis of linoleate and phosphatidic acid and its relationship to oil production in the microsomes of developing seeds of safflower (Carthamus tinctorius, L. var. Gila)

Stobart, A. K.; Stymne, Sten; Glad, Gunnar

doi:10.1016/0005-2760(83)90145-5

Cited by 30 publications

(18 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their hypothesis is partially based on the differential labelling of the fatty acids on the two sn positions of PC after "%C-labelling [9] and the demonstration of an active acyl-CoA : lyso-PC acyl transferase [21] in leaves of leek seedlings. Stymne et al [4] and Stobart et al [6] also showed differential turnover or exchange of fatty acid from acyl-CoA with the sn-2 position of PC in microsomes from developing safflower seeds. Analyses of molecular species of PC from potato microsomes [19] and sunflower seeds [7] showed similar uneven incorporation of label in itro after feeding with ["%C]oleoyl-CoA.…”

Section: Scheme 1 Outline Of the Pathways Of Biosynthesis And Desaturmentioning

confidence: 93%

See 1 more Smart Citation

The role of phosphatidylcholine in fatty acid exchange and desaturation in Brassica napus L. leaves

Williams¹,

Imperial

Khan

et al. 2000

Biochemical Journal

View full text Add to dashboard Cite

The role of phosphatidylcholine (PC) in fatty acid exchange and desaturation was examined and compared with that of monogalactosyldiacylglycerol (MGDG) in Brassica napus leaves using "%C-labelling in i o. Data are presented which indicate that in the chloroplast newly formed saturated (palmitic acid, 16 : 0) and monounsaturated (oleic acid, 18 : 1) fatty acid is incorporated into MGDG and desaturated in situ. In the non-plastidic compartments, however, newly formed fatty acid is exchanged with polyunsaturated fatty acid in PC, the probable major site of subsequent desaturation. The unsaturated fatty acid is released to the acyl-CoA pool, which is then used to synthesize di-

show abstract

Section: Scheme 1 Outline Of the Pathways Of Biosynthesis And Desaturmentioning

confidence: 93%

“…In seeds a similar pathway is hypothesized except that there is some exchange of fatty acid between PC and the acyl-CoA prior to DAG and TAG synthesis [6,7]. The desaturation of fatty acids in PC determines the levels of unsaturated fatty acids in the DAG precursors of seed TAG and the chloroplast lipids [8].…”

Section: Introductionmentioning

confidence: 99%

The role of phosphatidylcholine in fatty acid exchange and desaturation in Brassica napus L. leaves

Williams¹,

Imperial

Khan

et al. 2000

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…Roughan & Slack (1982) suggest that the phosphatidylcholine gives rise to polyunsaturated species of diacylglycerols that are further acylated to yield triacylglycerol. We have shown in microsomal preparations, however, that the oleate in oleoyl-CoA equilibrates with linoleate in position 2 of sn-phosphatidylcholine (Stymne et al, 1983;Stobart et al, 1983;Stymne & Stobart, 1984a) and that this is probably catalysed by the forward and reverse reactions of an acyl-CoA :lysophosphatidylcholine acyltransferase enzyme working in concert (Stymne & Stobart, 1984b). The acyl exchange returns linoleate to the acyl-CoA pool where it is selectively utilized in the acylation of sn-glycerol 3-phosphate to give phosphatidate (Stymne et al, 1983;Stobart et al, 1983), which in its turn is converted into diacyland tri-acylglycerol by the reactions of the 'Kennedy' (1961) pathway .…”

mentioning

confidence: 90%

“…We have shown in microsomal preparations, however, that the oleate in oleoyl-CoA equilibrates with linoleate in position 2 of sn-phosphatidylcholine (Stymne et al, 1983;Stobart et al, 1983;Stymne & Stobart, 1984a) and that this is probably catalysed by the forward and reverse reactions of an acyl-CoA :lysophosphatidylcholine acyltransferase enzyme working in concert (Stymne & Stobart, 1984b). The acyl exchange returns linoleate to the acyl-CoA pool where it is selectively utilized in the acylation of sn-glycerol 3-phosphate to give phosphatidate (Stymne et al, 1983;Stobart et al, 1983), which in its turn is converted into diacyland tri-acylglycerol by the reactions of the 'Kennedy' (1961) pathway . We have also demonstrated an equilibration between diacylglycerol and phosphatidylcholine, possibly catalysed by a CDP: diacylglycerol cholinephosphotransferase (Slack, 1983;Slack et al, 1983), which occurs when glycerol backbone flows from phosphatidate to triacylglycerol (Stymne & Stobart, 1984a).…”

mentioning

confidence: 90%

The acylation of sn-glycerol 3-phosphate and the metabolism of phosphatidate in microsomal preparations from the developing cotyledons of safflower (Carthamus tinctorius L.) seed

Griffiths¹,

Stobart²,

Stymne³

1985

Biochemical Journal

View full text Add to dashboard Cite

Microsomal preparations from the developing cotyledons of safflower (Carthamus tinctorius) catalysed the acylation of sn-glycerol 3-phosphate in the presence of acyl-CoA. The resulting phosphatidate was further utilized in the synthesis of diacyl- and tri-acylglycerol by the reactions of the so-called 'Kennedy pathway' [Kennedy (1961) Fed. Proc. Fed. Am. Soc. Exp. Biol. 20, 934-940]. Diacylglycerol equilibrated with the phosphatidylcholine pool when glycerol backbone, with the associated acyl groups, flowed from phosphatidate to triacylglycerol. The formation of diacylglycerol from phosphatidate through the action of a phosphatidate phosphohydrolase (phosphatidase) was substantially inhibited by EDTA and, under these conditions, phosphatidate accumulated in the microsomal membranes. The inhibition of the phosphatidase by EDTA was alleviated by Mg2+. The presence of Mg2+ in all incubation mixtures stimulated quite considerably the synthesis of triacylglycerol in vitro. Microsomal preparations incubated with acyl-CoA, sn-glycerol 3-phosphate and EDTA synthesized sufficient phosphatidate for the reliable analysis of its intramolecular fatty acid distribution. In the presence of mixed acyl-CoA substrates the sn-glycerol 3-phosphate was acylated exclusively in position 1 with the saturated fatty acids, palmitate and stearate. The polyunsaturated fatty acid linoleate was, however, utilized largely in the acylation of position 2 of sn-glycerol 3-phosphate. The affinity of the enzymes involved in the acylation of positions 1 and 2 of sn-glycerol 3-phosphate for specific species of acyl-CoA therefore governs the non-random distribution of the different acyl groups in the seed triacylglycerols. The acylation of sn-glycerol 3-phosphate in position 1 with saturated acyl components also accounts for the presence of these groups in position 1 of sn-phosphatidylcholine through the equilibration of diacylglycerol with the phosphatidylcholine pool, which occurs when phosphatidate is utilized in the synthesis of triacylglycerol. These results add further credence to our previous proposals for the regulation of the acyl quality of the triacylglycerols that accumulate in developing oil seeds [Stymne & Stobart (1984) Biochem. J. 220, 481-488; Stobart & Stymne (1985) Planta 163, 119-125].

show abstract

“…In addition to its economical and agricultural value, safflower is considered as a good biological material for carrying out a fundamental research on the biosynthesis of polyunsaturated fatty acids (Browse and Slack 1983;Stobart et al 1983;Stobart and Stymne 1985). Therefore, in this work the accumulation of lipids during the formation and maturation of safflower seeds was followed.…”

Section: Introductionmentioning

confidence: 99%

Glycerolipid Evolution During Safflower Seed Formation and Ripening

Sellami

Touati

Dhifi

et al. 2004

Journal of Food Lipids

View full text Add to dashboard Cite

Lipid accumulation during formation and ripening of safflower seeds by plants cultivated in the north‐west of Tunisia was evaluated. The results obtained showed an increase in oil content and total lipids. At the level of fatty acids, seed replenishment resulted mainly in an increase in the rate and the amounts of linoleic acid (C18:2), the major fatty acid identified in seeds (75% of total fatty acids). The ripening process of safflower seeds was also characterized by an increase in the content of triacylglycerols (TAG) and a decrease in the diacylglycerols (DAG), phosphatidylcholine (PC) and phosphatidic acid (PA) contents. To explain these results, the hypothesis of TAG biosynthesis from PC and PA via DAG was advanced and discussed. Finally, ripening of safflower seeds was characterized by a decrease in the amounts of main galactolipids, indicating a decrease of the photosynthetic activity in storage tissues.

show abstract

The synthesis of linoleate and phosphatidic acid and its relationship to oil production in the microsomes of developing seeds of safflower (Carthamus tinctorius, L. var. Gila)

Cited by 30 publications

References 17 publications

The role of phosphatidylcholine in fatty acid exchange and desaturation in Brassica napus L. leaves

The role of phosphatidylcholine in fatty acid exchange and desaturation in Brassica napus L. leaves

The acylation of sn-glycerol 3-phosphate and the metabolism of phosphatidate in microsomal preparations from the developing cotyledons of safflower (Carthamus tinctorius L.) seed

Glycerolipid Evolution During Safflower Seed Formation and Ripening

Contact Info

Product

Resources

About