PURIFICATION, CHARACTERIZATION, AND IMMUNOLOCALIZATION OF A THIOREDOXIN REDUCTASE FROM ADULT FASCIOLA HEPATICA

• Published in: The Journal of parasitology Vol. 90; no. 2; pp. 205 - 211
• Main Authors: Maggioli, Gabriela, Piacenza, Lucía, Carambula, Beatriz, Carmona, Carlos
• Format: Journal Article
• Language: English
• Published: United States American Society of Parasitologists 01.04.2004
• Subjects: Animals; Antiserum; Aurothioglucose - pharmacology; Biochemistry; BIOCHEMISTRY-PHYSIOLOGY; Cattle; Chemical Fractionation; Chromatography, Affinity; Chromatography, Ion Exchange; Disulfides; Electrophoresis, Polyacrylamide Gel; enzyme activation; enzyme activity; enzyme inhibition; enzyme inhibitors; Enzyme Inhibitors - pharmacology; Enzymes; Fasciola hepatica; Fasciola hepatica - enzymology; Fluorescent Antibody Technique; Immunoblotting; immunochemistry; Immunoglobulin G - immunology; Insulin; liver flukes; oxidoreductases; Parasites; Parasitology; purification; Room temperature; Sulfates; Thioredoxin; Thioredoxin-Disulfide Reductase - antagonists & inhibitors; Thioredoxin-Disulfide Reductase - immunology; Thioredoxin-Disulfide Reductase - isolation & purification; Thioredoxin-Disulfide Reductase - metabolism; tissue distribution
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/GE-3247

Thioredoxin reductase (TrxR), an enzyme belonging to the flavoprotein family of pyridine nucleotide-disulfide oxidoreductases, was isolated from the deoxycholate-soluble extract of the common liver fluke, Fasciola hepatica. Purification to homogeneity of the 60-kDa enzyme from the adult worm was achieved by a combination of ammonium sulfate fractionation, anion exchange, and affinity chromatography on 2′,5′-adenosine diphosphate–Sepharose. Using the 5,5′-dithiobis(2-nitrobenzoic acid) assay, the purified TrxR showed a specific activity of 7,117 U min−1 mg−1. The enzyme activity was completely inhibited by the presence of the gold compound aurothioglucose (IC50 = 120 nm), indicating that F. hepatica TrxR is a selenoenzyme. Also, the enzyme was capable of reducing disulfide bonds in insulin and was activated by the presence of the reduced form of flavin adenine dinucleotide, properties shared with mammalian TrxRs. Furthermore, the isolated enzyme showed very low glutaredoxin (Grx) activity (0.47 U mg−1), but no glutathione reductase activity was detected. Affinity-purified IgGs (20 μg ml−1) from the antisera produced against the purified TrxR inhibited its activity about 80% with respect to the control. The enzyme was immunolocalized in cells located within the parenchyma and in the testes, but it was not found in the tegument of the adult fluke.