****************************************************************************** From: Iris Klaiber Date: Mon, 13 Jan 1997 22:25:26 +0100 Subject: 3-Hydroxy-palmiticacid Organization: CC University of Hohenheim (not responsible for contents) We are searching for 3-Hydroxy-palmiticacid (or another 3-Hydroxy-fatty- acid) as reference component to determine the configuration of our isolated one, which we have only in a very small amount. Does anyone have a method, or a reference to a method, for the determination of the configuration (R or S) with an maximum of 0.3 mg? Thanks in advance for any answers. Iris _______________________________________________________________ Iris Klaiber email: klaib130@uni-hohenheim.de University of Hohenheim Tel.: ++49-711-459-2248 Dep. for Chemistry Fax.: ++49-711-459-2951 Garbenstr. 30 70599 Stuttgart Germany ______________________________________________________________ ****************************************************************************** From: mrdio007@aol.com (MrDio007) Date: 19 Jan 1997 18:32:49 GMT Subject: Re: 3-Hydroxy-palmiticacid Organization: AOL http://www.aol.com In the process of investigating the fatty acid synthesis pathway of bacteria I was forced to synthesize 3-Hydroxy-Decynoyl NAC(ie you might not be able to buy it) I am pretty sure that the enzyme pathways are stereospecific for one isomer over another. The Cycle of FA synthesis produces the 3-0H configuration . This is stereospecific in E.Coli (and most others I'd imagine)Because the subsequent step in which the 3-OH form is utilized has a stereospecific requirement. I Quote; Beta-Ketoacyl-ACP reductase The reaction product of acetoacetyl-ACP has the D(-) configuration. Beta-Hydroxyacyl-ACP dehydrasae The enzyme (beta-hydroxyacyl-ACP dehydrase) catalyses the dehydration of D(-)-beta-hydroxyacyl-ACP thioesters to form trans-2-enoyl-ACP thioesters... Like the beta-ketoacyl-ACP synthetase, the dehydrase has an absolute specificity for thioesters of ACP; it is inactive with thioesters of CoA or pantetheine. The reaction is stereospecific; the D(-) isomer of beta-hydroxybutryl-ACP was dehydrated whereas the L(+) isomer was not. pg 123 Quotes from Biochemistry of Lipids Ed. TW Goodwin, F.R.S. Vol. 4 of the MTP International Review of Science Series 1974 ISBN 0-8391-1043-X Butterworth and Co. Pub. You might also check out Morris Kates' "techniques of lipidology" Elsevier (2nd ed 1986) This guy is the GOD of lipids in my opinion. he says on pg 34 "The b-hydroxy saturated acids form a series of even-carbon acids...3-Hydroxy acids are fairly widespread in yeasts and bacteria, usually occuring as D(-) isomers in ester bound or glycosidic forms in extracellular lipids. For example, 3-D-OH-C10,-C12,-C14 acids are constituents of lippopolysaccharides in cell walls of Gram-Negative Bacteria (Kaneshiro & Marr 1963 Biochim.Biophys.Acta, 70,271); 3-D-hydroxy-C10 acid occurs in the rhamno-lipid of Pseudomonas aeruginosa (Jarvis and Johnson 1949, JACS, 71,4124)...(another ref...Tulloch and Spencer1964, Can.J.Chem.42,830)..The D-3-OH acids are also intermediates in the beta-oxidation pathway of fatty acids." Many people (eg. Julie Leary et al) have been using the addition of Metals to differentiate various types of isomers using mass spec. If you have some standards in D and L forms and you have a mass spec you could develop a method. Otherwise maybe one of the old papers have methods (bucket loads of sample ?) Source of the material combined with literature info may tell you indirectly the D/L of what you have. John Cronan is another awesome lipid guy (U Ill ?) good luck Matt Sweeney good luck ******************************************************************************