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The specific activities of 12 of the enzymes involved in glucose metabolism were adapted by Trichomonas vaginalis, a human genito-urinary tract parasite, to the growth rate and glucose availability. A strong correlation to each other was observed in the specific activities of the enzymes, with the sole exception of lactate dehydrogenase. Production rates of the three major end-products, namely, lactate, acetate and glycerol, increased as growth rates rose. Growth rates and glucose availability were also found to strongly affect the ratio of the end products. Production rates of glycerol and acetate were heavily controlled by the specific activities of the enzymes catalyzing the final reactions of their respective pathways.

Levels of mRNAs encoding metabolic enzymes and their cellular activities were assessed on continuous culture samples of the parasitic protists Trypanosoma brucei and Trichomonas vaginalis. The bacteria were grown in chemostats at different growth rates under glucose limitation or in the presence of excess glucose, causing extensive adaptation of the cellular activities of glycolytic enzymes. Findings showed that RNA levels in Trypanosoma brucei and Trichomonas vaginalis are determined by growth rate and in the latter species by the presence of the carbon and energy source.