α-AMINOADIPIC ACID AS A PRECURSOR TO LYSINE IN NEUROSPORA

In a recent investigation reported by Mitchell and Houlahan (1) it was shown that a mutant strain of Neurospora crassa, strain 33933, was able to utilize α-aminoadipic acid in place of lysine. Although these authors interpreted their results as showing that oc-aminoadipic acid was a precursor in the biosynthesis of lysine by Neurospora, other pathways are conceivable. the isolation of α-aminoadipic acid from a natural protein radioactive α-aminoadipic acid was added as a marker for chromatographic analysis (2). In order to identify the isolated amino acid an aliquot was provided as a growth substance for the Neurospora mutant 33933. Thus the opportunity was available to follow the radioactivity and determine whether or not α-aminoadipic acid was a precursor to lysine.