1. Improving enzymatic activities and thermostability of a tri-functional enzyme with SOD, catalase and cell-permeable activities.
- Author
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Luangwattananun P, Eiamphungporn W, Songtawee N, Bülow L, Isarankura Na Ayudhya C, Prachayasittikul V, and Yainoy S
- Subjects
- Animals, Antioxidants metabolism, Catalase metabolism, Cell Line, Cell Membrane Permeability, Cell Movement drug effects, Half-Life, Mice, Molecular Weight, Oxidative Stress drug effects, Paraquat adverse effects, Recombinant Proteins metabolism, Antioxidants pharmacology, Catalase genetics, Protein Engineering methods, Recombinant Proteins pharmacology, Superoxide Dismutase genetics
- Abstract
Synergistic action of major antioxidant enzymes, e.g., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) is known to be more effective than the action of any single enzyme. Recently, we have engineered a tri-functional enzyme, 6His-MnSOD-TAT/CAT-MnSOD (M-TAT/CM), with SOD, CAT and cell-permeable activities. The protein actively internalized into the cells and showed superior protection against oxidative stress-induced cell death over native enzymes fused with TAT. To improve its molecular size, enzymatic activity and stability, in this study, MnSOD portions of the engineered protein were replaced by CuZnSOD, which is the smallest and the most heat resistant SOD isoform. The newly engineered protein, CAT-CuZnSOD/6His-CuZnSOD-TAT (CS/S-TAT), had a 42% reduction in molecular size and an increase in SOD and CAT activities by 22% and 99%, respectively. After incubation at 70°C for 10min, the CS/S-TAT retained residual SOD activity up to 54% while SOD activity of the M-TAT/CM was completely abolished. Moreover, the protein exhibited a 5-fold improvement in half-life at 70°C. Thus, this work provides insights into the design and synthesis of a smaller but much more stable multifunctional antioxidant enzyme with ability to enter mammalian cells for further application as protective/therapeutic agent against oxidative stress-related conditions., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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