Abstract
A relationship between spatial configuration and serological specificity has been established in several instances. 1 , 2 , 3 , 4 In recent studies it has been found that the cis-trans isomerism of maleic and fumaric acid can be detected serologically. The immune serum used was obtained by injection of an antigen consisting of protein to which was coupled diazotized p-aminosuccinanilic acid. The reaction of this immune serum with the corresponding antigen was inhibited by succinic acid (as sodium salt) and moreover by maleic, but not by fumaric acid. This differentiation of the cis and transforms extended to the monoesters of the two acids and furthermore to the methyl substituted compounds (citraconic and mesaconic acid).
On the basis of our former results the suggestion was made 5 that in certain cases serological reactions could be used for determining spatial configuration, in a way similar to that in which enzymes have been applied to this purpose. At the same time a first example was cited dealing with the correlation between the optically active forms of malic and tartaric acids. Since no details have been given, a description of the experiments will follow.
For the tests immune sera were used specific for levo and dextrotartaric acids, prepared as described previously 2 and in addition an immune serum specific for levo-malic acid. This was obtained by injections of rabbits with an antigen made by coupling diazotized levo-para-aminomalanilic acid to horse serum. Levo and dextrorotatory para-aminomalanilic acids were prepared by reduction of the corresponding nitro-compounds.∗ For the preparation of these compounds the two optically active malic acids were condensed with para-nitraniline. ∗ Which of the two possible levo or dextro-nitranilides the substances isolated represent remains to be determined; but it seems probable that the condensation would take place more readily with the carboxyl next to the hydroxyl group.
Get full access to this article
View all access options for this article.