Abstract
The biosynthesis of altenin is discussed in this paper. The altenin toxicity of culture broth appeared and reached to a maximum, after the speed of growth of Alternaria Kikuchiana Tanaka slowed down. The culture broth contained uronic acid, the content of which increased with the period of growth of the cell, and then decreased to a minimum on the eighteenth day, when the toxicity was a maximum. A solution of glucuronic acid did not exhibit the altenin toxicity, but when the cellfree extraction of this fungus was added, the toxicity was observed after one day. From these facts, it seems reasonable to assume that, in this cultivation, uronic acid was produced as an intermediate, and then changed to altenin by the enzyme which is produced in the cell.
