The separation of amino-acids by means of their copper salts

Abstract

THE study of the-hydrolysis of gliadin described in this paper was started during the tenure of an Alexander Brown Coxe Research Fellowship at Yale University during the year 1931-32. It is gradually being completed with a view to obtaining as complete a picture as possible of the disposition of the amino-acids in their separation by means of their copper salts.In the original paper [Town, 1928] three fractions were obtained by separating the copper salts of the amino-acids into:1. Those soluble in methyl alcohol.2. Those soluble in water, but insoluble in methyl alcohol.3. Those insoluble in water.In a later paper [Town, 1936] the methyl alcohol-soluble copper salt fraction was further subdivided into (a) a part precipitated by alcoholic CdCl2 and (b) the filtrate. The examination of the CdCl2 precipitate, which contains the proline, was fully reported.Modifications were introduced into this hydrolysis as a result of experience gained in previous hydrolyses. Important technical improvements were as follows.

The 3:5-dinitrobenzoyl derivatives of the amino-acids and their use in separating the isomers of leucine and valine

“…This-is believed to be the derivative of r-glutamic acid; it is certainly not that of dl-glutamic acid which gives the derivative M.P. 1040 [Town, 1941].…”

“…This derivative crystallizes in long narrow rectangular plates. A derivative was also prepared from the isoleucine isolated from gliadin by Town [1929], and this also had M.P. 1700.…”