A gene has been cloned from Trypanosoma brucei which encodes a protein of 144 amino acid residues containing the thioredoxin-like motif WCPPCR. Overexpression of the gene in E. coli resulted in 4 mg pure protein from 100 ml bacterial cell culture. Recombinant T. brucei tryparedoxin acts as a thiol-disulfide oxidoreductase. It is spontaneously reduced by trypanothione. This dithiol, exclusively found in parasitic protozoa, also reduces E. coli glutaredoxin but not thioredoxin. The trypanothione/tryparedoxin couple is an effective reductant of T. brucei ribonucleotide reductase. Like thioredoxins it has a poor GSH:disulfide transhydrogenase activity. The catalytic properties of tryparedoxin are intermediate between those of classical thioredoxins and glutaredoxins which indicates that these parasite proteins may form a new class of thiol-disulfide oxidoreductases.
Lüdemann, H., Dormeyer, M., Sticherling, C., Stallmann, D., Follmann, H., & Krauth-Siegel, R. L. (1998). Trypanosoma brucei tryparedoxin, a thioredoxin-like protein in African trypanosomes. FEBS Letters, 431(3), 381–385. https://doi.org/10.1016/S0014-5793(98)00793-5