Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 10, 2008
Publication Date: May 17, 2008
Citation: Lin, J.T. 2008. Regiospecific Indentification of 2-(12-Ricinoleoylricinoleoyl)-1,3-diricinoleoyl-glycerol in Castor Oil by Mass Spectrometry and sn-1,3 Specific Lipase. American Oil Chemists Society, May 18-21, Seattle, WA. Interpretive Summary: A tetraacylglycerol containing four hydroxyl fatty acids was reported recently in castor oil. This biobased product can be used in industry for the manufacture of lubricants and polymers. We have identified the location of an acylacyl chain at the sn-2 position on the glycerol backbone of this tetraacylglycerol. This will help to understand the biosynthetic pathway of this compound which can then be used to overproduce it by genetic engineering. The location of an acylacyl chain on the glycerol backbone can affect the physical property of this oil, e.g., viscosity and pour point.
Technical Abstract: (12-Ricinoleoylricinoleoyl)diricinoleoylglycerol (RRRR), a tetraacylglycerol, was identified earlier in castor oil. Using ESI-MS4, 95% of the 12-ricinoleoylricinoleoyl chain was identified at the sn-2 position on the glycerol backbone of RRRR. Regiospecific location of the 12-ricinoleoylricinoleoyl chain of RRRR on the glycerol backbone was identified and quantified by the ions from the losses of the acyl chains at the sn-2 position as a,ß-unsaturated fatty acids from the lithium adduct of RRRR. The regiospecific location was confirmed by hydrolysis of RRRR using sn-1,3 specific lipase. By comparison to the mass spectrum of 1-O-palmityl-2,3-palmitoyl-rac-glycerol containing one ether bond, the 12-ricinoleoylricinoleoyl chain of RRRR is indeed the ester bond between the two ricinoleoyl chains, not the ether bond formed from the two hydroxyl groups of the two ricinoleoyl chains.