Evidence for the involvement of a rapidly turning over protease in the degradation of cytochrome oxidase in Neurospora crassa

The reaction of L-aromatic aminoacid decarboxylase (EC 4.1.1.28) with α-methyl-L-DOPA or 5-hydroxy-L-tryptophan leads to the formation of dihydroxyphenylacetone or, respectively, 5-hydroxyindolacetaldeyde. These are produced in amounts far exceeding, on molar basis, that of the coenzyme, pyridoxal-5′-phosphate. The reaction cannot therefore be simply a decarboxylation-dependent transamination, using the coenzyme as an amino group acceptor. Evidence is presented which rules out the possibility that this phenomenon is due to an oxidative deamination.