SPECTROSCOPICAL STUDY OF AMINO-ACID ANHYDRIDES. II. LIGHT ABSORPTIONS OF SOME AMINO-ACIDS, THEIR ESTERS, PEPTIDES AND ANHYDRIDES

Abstract

Abstract (1) Glycocoll, alanine, leucine, phenylalanine, tyrosine, glycocoll ester, tyrosine esters, glycylleueine, glycyl-l-phenylalanine, glycyl-d,l-phenyl alanine, glycyl-l-tyrosine anhydride, tyrosine anhydride, glycyl-l-leucine anhydride, leucine anhydride, glycyl-l-phenylalanine anhydride and phenylalanine anhydride were spectrochemically studied in aqueous, alcoholic or glacial acetic acid solutions. (2) Among these compounds only those which contain phenyl and oxy-phenyl groups in their molecules show selective light absorptions ; i.e., tyrosine, phenylalanine and their derivatives, except phenylalanine, anhydride absorb selectively. (3) Although two phenyl groups exist in its molecule, phenylalanine anhydrid show only end absorption, perhaps due to the mutual effect of these two chromophores symmetrically situated to each other. (4) Derivatives of either tyrosine or phenylalanine absorb identically with their mother substances. (5) Other amino-acids, their esters, pepetides and anhydrides show no selective absorptions, as in the cases of glycocoll anhydride, alanine anhydride and sarcosine anhydride which were described in our previous paper. (6) As for the constitution of amino-acid anhydrides, the same conclusion as was previously mentioned, may be applied again to the substances now studied, that is to say, all these anhydrides are in keto-form.