Monoaminodicarboxylic acids

C. Monoaminodicarboxylic acids and their amides Aspartic acid Asparagine Glutamic acid Glutamine... 

The third method of separating optically active substances by combining them with optically active bases or acids had not been employed with any success until E. Fischer took up this question, the study of the optically active amino acids being his first work upon the chemical constitution of the proteins. The non-success of this method was in all probability due to the small affinity which the simple amino acids themselves have for combining with acids and bases even the attempts to separate the monoaminodicarboxylic acids, which are fairly strong acids, were not successful. 

The hydrolysis of preparations such as Product II yielded trace of histidine, 14 per cent arginine, 5 per cent lysine, 15 per cent leucine, 10-14 per cent hydroxyproline, a monoaminodicarboxylic acid fraction including aspartic and glutamic acids, 41-45 per cent, 5 per cfflit glycine, and 15 per cent aminohexose. Complete absence of pyrimidine and purine bases, pentoses, and desoxyglucose was reported. 

Of many non-protein amino acids known in plants, only a few have been found in ferns. Several unusual monoaminodicarboxylic acids have been obtained, mainly from the genus Asplenium. Fifteen New Zealand species of Asplenium contain (25,4i )-4-methyl-L-glu-tamic acid (848), (25)-4-hydroxy-4-methylglutamic acid (849) and 5-iV-acetyl-L-ornithine (844), but these were not detected in two Athyr-ium spp., A. australe and A. japonicum 499). This fact provides additional support for the proposal that there is no close affinity between the two genera Asplenium and Athyrium 499). 

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