Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Incorporation of Laurate and Hydroxylaurate into Molecular Species of Pc and Ag in Castor Microsomes.

Authors
item Lin, Jiann-Tsyh
item Wani, Seiji
item Nguyen, Tasha
item McKeon, Thomas

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: January 14, 2005
Publication Date: May 1, 2005
Citation: Lin, J.T., Wani, S., Nguyen, T.T., Mckeon, T.A. 2005. Incorporation of laurate and hydroxylaurate into molecular species of pc and ag in castor microsomes.. Annual Meeting and Expo of the American Oil Chemists' Society. 82: pp.495-499(2005).

Interpretive Summary: Because castor produces oil with a high content of hydroxyl fatty acid (90% ricinoleate), we were interested in determining the flexibility of castor seed microsomes in incorporating other hydroxyl fatty acids. To this end, we incubated the [14C]-labelled 12:0 fatty acids (FA), laurate (La), 11-hydroxylaurate and 12-hydroxylaurate with castor microsomes that are capable of synthesizing castor oil. The molecular species of phosphatidylcholines (PC) and acylglycerols (AG) incorporating these non-endogenous FA of castor were identified by the reversed-phase C8 and C18 HPLC respectively. [14C]Laurate was incorporated into the molecular species of PC and AG at levels of 10% and 4% respectively, comparing to incorporation of [14C]ricinoleate. Similar to those from the incorporation of the six [14C]FA, ricinoleate (R), oleate (O), linoleate (L), linolenate (Ln), stearate (S) and palmitate (P) reported, the molecular species of PC incorporating [14C]laureate were LLa-PC > PLa-PC > OLa-PC > LnLa-PC > SLa-PC > RLa-PC. The molecular species of AG incorporating [14C]laurate were RRLa > LaLa > RLa > RLLa > ROLa > LOLa > LLLa > LLa > LLnLa > RSLa > OOLa. The retention times for lipids incorporating laurate are similar to those of lipids incorporating linolenate, because the equivalent carbon numbers of laurate and linolenate are the same. Relative retention times of the molecular species of PC and AG containing laurate are also reported here. The incorporation of 11-hydroxylaurate and 12-hydroxylaurate into PC and AG was not detected

Technical Abstract: The radiolabelled C12 fatty acids (FA), laurate (La), 11-hydroxylaurate and 12-hydroxylaurate were incubated in castor microsomes for the purpose of using transgenic castor to produce these fatty acids for industrial uses. The molecular species of phosphatidylcholines (PC) and acylglycerols (AG) incorporated from these non-endogenous FA of castor were identified by the reversed-phase C8 and C18 HPLC respectively. [14C]Laureate was incorporated into the molecular species of PC and AG at the levels of 10% and 4% respectively comparing to those incorporated from [14C]ricinoleate. The molecular species of PC incorporated from [14C]laureate were LLa-PC > PLa-PC > OLa-PC > LnLa-PC > SLa-PC > RLa-PC which were similar to those from the incorporation of the six [14C]FA, ricinoleate (R), oleate (O), linoleate (L), linolenate (Ln), stearate (S) and palmitate (P). The molecular species of AG incorporated from [14C]laureate were RRLa > LaLa > RLa > RLLa > ROLa > LOLa > LLLa > LLa > LLnLa > RSLa > OOLa. The radiochromatogram was similar to that from [14C]linolenate, because the partition numbers of laureate and linolenate are the same. The incorporations of 11-hydroxylaurate and 12-hydroxylaurate into PC and AG were not detected. Relative retention times of the molecular species of PC and AG incorporated from [14C]Laurate are also reported here.

Last Modified: 9/10/2014