Ribonucleoside diphosphate reductase consists of two nonidentical subunits, proteins Bl and B2. The enzyme catalyzes the reduction of ribonucleotides to the corresponding deoxyribonucleotides. The electrons required in this reduction are transported from NADPH via a flavoprotein, thioredoxin reductase, to a low molecular weight protein, thioredoxin. The reduced form of thioredoxin acts as hydro...

Thioredoxin is a low molecular weight protein. In the oxidized form, thioredoxin-S2, it contains a single disulfide bridge formed from the 2 half-cystine residues in the molecule (1). The reduced or dithiol form of thioredoxin, thioredoxin-(SH)z, was first identified as the hydrogen donor in the reduction of ribonucleotides to deoxyribonucleotides in Escherichia coli (2). It has now been shown ...

This study explored the effects of the antioxidant astaxanthin on paraoxonase and thioredoxin reductase activities as well as on other oxidative stress parameters and on the lipid profile in hypercholesterolemic rabbits. Rabbits were fed a standard or a hypercholesterolemic diet alone or supplemented with 50, 100 and 500 mg/100 g of astaxanthin for 60 days. Antioxidant enzymes activities, lipid...

The preceding paper (1) described the purification from Escherichia coli of thioredoxin, a heat-stable, small protein involved in the reduction of cytidine diphosphate to deoxycytidine diphosphate by the cytidine diphosphate reductase system isolated from E. coli (2). Evidence was presented that thioredoxin was first reduced enzymatically with TPNH to a sulfhydryl form (thioredoxin-(SH)J, which...

A group of bacterial flavoproteins related to thioredoxin reductase contain an additional approximately 200-amino-acid domain including a redox-active disulfide center at their N-termini. These flavoproteins, designated NADH:peroxiredoxin oxidoreductases, catalyze the pyridine-nucleotide-dependent reduction of cysteine-based peroxidases (e.g. Salmonella typhimurium AhpC, a member of the peroxir...

BACKGROUND Malaria, a scourge of mankind, imposes a huge socioeconomic burden in tropical countries. Emergence of multi-drug resistant malarial parasites impels us to explore novel drug targets. Thioredoxin reductase is a promising antimalarial drug target. METHODS The Thioredoxin reductase enzyme of Plasmodium falciparum was characterized in silico and protein disorder was predicted using av...

Thioredoxins (TRXs) are protein oxidoreductases that control the structure and function of cellular proteins by cleavage of a disulphide bond between the side chains of two cysteine residues. Oxidized thioredoxins are reactivated by thioredoxin reductases (TR) and a TR-dependent reduction of TRXs is called a thioredoxin system. Thiol-based redox regulation is an especially important mechanism t...

In this study herpes simplex virus type 1-encoded ribonucleotide reductase was shown to be able to utilize thioredoxin purified from the cyanobacterium Anabaena variabilis as a hydrogen donor for the enzyme. An assay has been developed to search for proteins which can function as a hydrogen donor for the viral ribonucleotide reductase. A protein has been identified and purified to homogeneity f...