Redox metabolism

Redox metabolism pathway of Coccidians, Toxoplasma gondii and Neospora caninum is similar to the redox metabolism pathway of Plasmodium falciparum in MPMP. This pathway shows the series of oxidation/reduction activities involved in removal of oxidative radicals such as superoxide anions, hydrogen peroxide and other toxic nucleophiles produced from different metabolic reactions. These reactive oxygen species cause oxidative damage to DNA, lipids and proteins. There are several antioxidant systems present in cells to protect them from these damages. This includes enzymes such as superoxide dismutase which reduces superoxide anion to H2O2 and catalase which reduces H2O2 to water and oxygen. The enzyme peroxiredoxin also reduces H2O2. The oxidised peroxiredoxin can be reduced back by thiols such as glutathione and thioredoxin. The glutathione system consists of glutathione and the enzymes glutathione peroxidase, glutathione reductase and glutathione S-transferase [1]. Glutathione is a tripeptide of glutamine-cysteine-glycine and synthesised de novo in two reactions steps. This glutathione synthesis is also included in this pathway. Glutathione peroxidase and glutathione S-transferase catalyse reduction of oxidative radicals by oxidising glutathione. Glutathione can be reduced back by glutathione reductase [1]. Another redox protein thioredoxin is important in reduction of ribonucleotides to deoxyribonucleotides and its partner thioredoxin reductase catalyses reduction of oxidised thioredoxin using NADPH as electron donor.

 

Enzyme EC Number Gene id
Peroxiredoxin 1.11.1.15 NCLIV_014020
Peroxiredoxin 1.11.1.15 NCLIV_030930
Peroxiredoxin 1.11.1.15 NCLIV_053640
Peroxiredoxin 1.11.1.15 NCLIV_062630
Catalase 1.11.1.6 NCLIV_032240
Glutathione peroxidase 1.11.1.9 NCLIV_048080
Superoxide dismutase (Mn) 1.15.1.1 NCLIV_058710
Superoxide dismutase (Fe) 1.15.1.1 NCLIV_058810
Superoxide dismutase (Fe) 1.15.1.1 NCLIV_058830
Ribonucleotide reductase 1.17.4.1 NCLIV_001550
Ribonucleotide reductase 1.17.4.1 NCLIV_052980
Glutathione reductase 1.8.1.7 NCLIV_061350
Glutathione reductase 1.8.1.7 NCLIV_063590
Thioredoxin reductase 1.8.1.9 NCLIV_053860
Glutathione S-transferase 2.5.1.18 NCLIV_014500
gamma-glutamylcysteine synthetase 6.3.2.2 NCLIV_032550
Glutathione synthase 6.3.2.3 NCLIV_046200
Thioredoxin none NCLIV_000840
Glutaredoxin none NCLIV_015460
Thioredoxin none NCLIV_032390
Thioredoxin none NCLIV_036500
Thioredoxin none NCLIV_036510
Glutaredoxin none NCLIV_037620
Glutaredoxin none NCLIV_038390
Thioredoxin none NCLIV_039420
Thioredoxin none NCLIV_041550
Thioredoxin none NCLIV_042480
Thioredoxin none NCLIV_043210
MRP and/or GSSG pumps none NCLIV_044060
Glutaredoxin none NCLIV_045900
Glutaredoxin none NCLIV_045930
Thioredoxin none NCLIV_047040
Thioredoxin none NCLIV_059730
Thioredoxin none NCLIV_060690
Glutaredoxin none NCLIV_065200