Tryptophan Desmolase of Neurospora

Preliminary to an examination of extracts from tryptophanless Neurospora mutants which presumably lack tryptophan desmolase, it seemed desirable to investigate the properties of this enzyme as obtained from a parental strain.Tryptophan desmolase, the enzyme which catalyzes the formation of tryptophan from indole and serine, was named by Gordon and Mitchell (1).The first suggestion that tryptophan is synthesized in Neurospora by the condensation of indole and serine resulted from experiments performed with whole mycelium by Tatum and Bonner (2).Soon after, Umbreit, Wood, and Gunsalus (3) obtained cell-free preparations from Neurospora mycelium which catalyzed this reaction.These workers also demonstrated that under appropriate conditions pyridoxal phosphate was a necessary cofactor for tryptophan synthesis by cell-free extracts.Further studies of tryptophan desmolase have now been performed.This paper will present a scheme for the partial purification of this enzyme and will describe several of its characteristics.