Trypanothione is the parasite analog of glutathione; this enzyme is the equivalent of glutathione reductase. NADP(+) + trypanothione = H(+) + NADPH + trypanothione disulfide Binds 1 FAD per subunit. Homodimer. The active site is a redox-active disulfide bond. Belongs to the class-I pyridine nucleotide-disulfide oxidoreductase family.