Phenazine compounds as carriers in the hexosemonophosphate system

Abstract

The Eh of a series of phenazine derivatives, detd. by potentiometric titration, were correlated with the electronic properties of the substituents. The activity of the phenazines and of some non-phenazine dyestuffs as carriers in the hexose-monophosphate system was detd. According to their activity, the substances fell into 4 groups. (1) Most active, phenazine methosulphate, methochloride and ethosulphate, Eh + 0.055 to +0.080; (2) moderately active, mono- and di-sulphonic acids derived from n-methylphenazine, Eh +0.13, + 0.23, pyocyanine, Eh[long dash]0.011 and its ethyl homologue. (3) Less active, brilliant cresyl blue and methylene blue. (4) Inactive. The most active of the above compounds had only about 1/250 th. of the turnover no. of the flavin enzyme, Eh[long dash]0.06. Structure was evidently more important than Eh in determining the activity of carriers for this system. The property common to the phenazines and flavin was the ability to form serniquinones, and the peculiar activity of these compounds in this system was probably due to this property. When phenazine methochloride was used instead of flavin enzyme, the Neuberg ester was attacked much less readily than the Robison ester; with flavin enzyme as carrier both were attacked at about the same rate. Carboxylase was inhibited by [image]/300 phenazine methochloride, not by pyocyanine or phenosafranine; suc-cinic dehydrogenase was inhibited by phenosafranine, but much less by phenazine methochloride in the concentration used. The hexosemonophosphate system was inhibited by iodide in low conc. The action of phenazine methochloride on the metabolism of tumour tissue was to increase respiration and diminish aerobic glycolysis.