Th.r Chrmistry of Mold Tissue

In view of the rather high percentage of nitrogen in molds it is surprising to note the scarcity of reports concerning their amino acid content. Few amino acids have been reported, and still fewer have been isolated and characterized by analysis and by the formation and examination of suitable derivatives. Leutine, both free (1) and combined (2), has been reported in Aspergillus aiger, but no report of the presence of isoleucine in molds has been found. By continuous extraction of the dry, defatted mycelium of Aspergillus sydowi with acetone for several weeks we have obtained a mixture of amino acids from which leucine and isoleucine have been isolated in considerable quantities and identified. It would thus appear that at least these two amino acids occur free in the mycelium, or that they are very loosely combined and are split off during drying and extraction of the material. In the separation and purification of a mixture of amino acids whose properties are so nearly alike as those of leucine and isoleucine considerable losses are inevitable. For this reason, the quantities isolated represent the minimum amounts present; the actual amounts present are undoubtedly much greater. Of the defatted mold, 0.39 per cent was isolated as leucine, and 0.87 per cent as isoleucine. However, if all the amino nitrogen of the extract is assumed to be due to leucine and isoleucine, these two amino acids were obtained to the extent of 2.3 per cent of the defatted mold.