and have a tendency to aggregate, indicating that formation of a second disulphide in the molecule is accompanied by denaturation of the structure. Reduction of oxidized thymus thioredoxin can be achieved by dithiothreitol or by NADPH and thioredoxin reductase representing a possible autocatalytic control mechanism. Another major difference between the mammalian and the E. coli thioredoxin syst...

Thioredoxin reductase (EC 1.6.4.5) is a widely distributed flavoprotein that catalyzes the NADPH-dependent reduction of thioredoxin. Thioredoxin plays several key roles in maintaining the redox environment of the cell. Like all members of the enzyme family that includes lipoamide dehydrogenase, glutathione reductase and mercuric reductase, thioredoxin reductase contains a redox active disulfide...

BACKGROUND The entry of HIV into its host cell is an interesting target for chemotherapeutic intervention in the life-cycle of the virus. During entry, reduction of disulfide bridges in the viral envelope glycoprotein gp120 by cellular oxidoreductases is crucial. The cellular thioredoxin reductase-1 plays an important role in this oxidoreduction process by recycling electrons to thioredoxin-1. ...

Recent publications make it evident that the thioredoxin± thioredoxin reductase system has come of age. The four minireviews presented here attempt to put this field in perspective. The system was first recognized in the early 1960s as the reductant of methionine sulfoxide and PAPS (3 0-phosphoadenosine-5 0-phosphosulfate) in yeast and of ribonucleotides in Escherichia coli [1±3]. It became cle...

A scheme is described for the large scale purification of thioredoxin, thioredoxin reductase, and glutathione reductase. The scheme is based on an initial separation of thioredoxin from the two reductases by affinity chromatography on agarose-bound N6-(6-aminohexyl)-adenosine 2',5'-bisphosphate (agarose-2',5'-ADP). The two reductases were then separated by hydrophobic chromatography and purifie...

Seven independently isolated glutathione reductase-deficient (gor) Escherichia coli mutants were found to have an in vivo glutathione redox state that did not significantly differ from that of the parental strain, 98 to 99% reduced. Strains containing both a gor mutation and either a trxA mutation (thioredoxin deficient) or a trxB mutation (thioredoxin reductase deficient) were able to maintain...

Ribonucleotide reductases (EC 1 .I 7.4.1 and EC 1.17.4.2) catalyse the reduction of ribonucleoside 5’-diphosphates or triphosphates to the corresponding 2’-deoxyribonucleotides and are key enzymes for the onset of DNA replication during the cell cycle (Reichard, 1968; Follmann, 1974). The reduction of the 2’-hydroxyl group of the ribose moiety in a ribonucleotide is dependent on NADPH, but this...

Selenium participates in the antioxidant defense mainly through a class of selenoproteins, including thioredoxin reductase. Epigallocatechin-3-gallate (EGCG) is the most abundant and biologically active catechin in green tea. Depending upon the dose and biological systems, EGCG may function either as an antioxidant or as an inducer of antioxidant defense via its pro-oxidant action or other unid...