O2-POLAROGRAPHIC STUDIES ON SOLUBLE AND MITOCHONDRIAL ENZYMES OF CRITHIDIA FASCICULATA - GLYCEROPHOSPHATE ENZYMES

SYNOPSIS. Mitochondrial and supernatant fractions were isolated from Crithidia fasciculata by grinding with neutral alumina and differential centrifugation. Supernatant fractions contained at least 2 NAD‐linked enzymes: an α‐glycerophosphate dehydrogenase and a malate dehydrogenase. The properties of these enzymes were investigated polarographically with phenazine ethosulfate acting as electron acceptor. Agaricic acid, cinnamic acid and p‐NO2‐cinnamic acid were specific inhibitors of the α‐glycerophosphate dehydrogenase. Succinate, malate, DL‐α‐glycerophosphate and NADH stimulated respiration of mitochondrial preparations; O2 uptake was greatest with succinate. KCN and antimycin A inhibited succinate respiration more than α‐glycerophosphate respiration. Amytal did not affect succinate, α‐glycerophosphate or NADH oxidation. The trypanocide suramin inhibited mitochondrial respiration at least 77% with each substrate. The relevance of these results to other members of the Trypanosomatidae is discussed. Copyright © 1968, Wiley Blackwell. All rights reserved