Active recombinant thioredoxin h protein with antioxidant activities from sweet potato (Ipomoea batatas [L.] Lam Tainong 57) storage roots.
Recombinant thioredoxin h (Trx2) overproduced in Escherichia coli (M15) was purified by Ni2+-chelated affinity chromatography. The molecular mass of Trx2 is approximately 1.4 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Total antioxidant status, 1,1-diphenyl-2-picrylhydrazyl (DPPH) staining, reducing power method, Fe2+-chelating ability, ferric thiocyanate (FTC) method, and protection of calf thymus DNA against hydroxyl radical-induced damage were studied. The thioredoxin h protein with a concentration of 12.5 mg/mL exhibited the highest activity (expressed as 0.37 +/- 0.012 mM ABTS* radical cation being cleared) in a total antioxidant status test. In the DPPH staining thioredoxin h appeared as white spots when it was diluted to 50 mg/mL (a final amount of 15 microg). Like the total antioxidant status, the reducing power, Fe2+-chelating ability, FTC activity, and protection against hydroxyl radical-induced calf thymus DNA damage were found with the thioredoxin h protein. It was suggested that thioredoxin h might contribute to its antioxidant activities against hydroxyl and peroxyl radicals.
Huang
Dong-Jiann
DJ
Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan.
Chen
Hsien-Jung
HJ
Hou
Wen-Chi
WC
Lin
Chun-Der
CD
Lin
Yaw-Huei
YH
D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects; D004926:Escherichia coli / Q000378:metabolism; D027723:Ipomoea batatas / Q000737:chemistry*; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000737:chemistry*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D054480:Thioredoxin h; D013879:Thioredoxins / Q000032:analysis / Q000096:biosynthesis* / Q000494:pharmacology*
D000975:Antioxidants; D011994:Recombinant Proteins; D054480:Thioredoxin h; D013879:Thioredoxins