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LEIN OG, SHULGIN AT, GAL EM, GREENBERG DM.
“Feasibility of quantitative separation of the threo- and erythro-forms of amino-acids by column chromatography”.
Nature. 1952 Apr 01;169(4304):707.
The methods that are at present available for the
separation of the diastereoisomeric forms of aminoacids are subject to several limitations. In the usual fractionation procedures only one of the isomers, at most, is obtained pure, the other remaining contaminated. A high degree of purity is realized only at the expense of yield. The difficulties inherent in isotopic synthesis make the. above operations increasingly wasteful, thus further limiting the practicability of these methods.
We wish to report that the application of column chromatography, using an ion-exchange resin ('Dowex-50', 250/500 mesh), led to the clean-cut and quantitative separation of dl-threonine and dlallothreonine. On the scale employed (3 mM), the chromatographic separation was complete, whereas chemical separation, although yielding microbiologically pure dl-threonine, resulted in a dl-allothreonine fraction containing much of the threo-form. The carbon-14 labelled products of both chemical and chromatographic separation have been tested for purity by microbiological assay with L. faecales.
The quantitative recovery, the completeness of the separation and the economy of effort resulting from the use of the chromatographic procedure offer great advantages. The investigation is being extended to other f3-substituted serines and isoleucine. Detaile of this work will be published elsewhere.