m‐Chlorobenzhydroxamic Acid–an Inhibitor of Cyanide‐Insensitive Respiration in Trypanosoma brucei*

SYNOPSIS Cyanide‐insensitive respiration of bloodstream and culture forms of T. brucei was inhibited by m ‐chlorobenz‐hydroxamic acid ( m ‐CLAM). The cyanide‐sensitive respiration of culture forms of this organism was not affected by m ‐CLAM. This compound is the 1st really effective inhibitor to be described that acts specifically on the cyanide‐insensitive respiration of the T. brucei group of trypanosomes; as such it may be of some importance as a trypanocidal drug. Evidence is adduced which suggests that a branched electron transport chain is present in culture forms of T. brucei and that the cyanide‐insensitive terminal oxidase found in these stages is the same as that found in bloodstream forms.