:Ribonucleoside-triphosphate reductase

{{Infobox enzyme

| Name = Ribonucleoside-triphosphate reductase

| EC_number = 1.17.4.2

| CAS_number = 9068-66-0

| GO_code =

| image = 4coj.jpg

| width = 270

| caption = Ribonucleoside-triphosphate reductase dimer, Thermotoga maritima

}}

Ribonucleoside-triphosphate reductase ({{EC number|1.17.4.2}}, ribonucleotide reductase, 2'-deoxyribonucleoside-triphosphate:oxidized-thioredoxin 2'-oxidoreductase) is an enzyme with systematic name 2'-deoxyribonucleoside-triphosphate:thioredoxin-disulfide 2'-oxidoreductase.{{cite journal | vauthors = Blakley RL | title = Cobamides and ribonucleotide reduction. I. Cobamide stimulation of ribonucleotide reduction in extracts of Lactobacillus leichmannii | journal = The Journal of Biological Chemistry | volume = 240 | pages = 2173–80 | date = May 1965 | pmid = 14299643 }}{{cite journal | vauthors = Goulian M, Beck WS | title = Purification and properties of cobamide-dependent ribonucleotide reductase from Lactobacillus leichmannii | journal = The Journal of Biological Chemistry | volume = 241 | issue = 18 | pages = 4233–42 | date = September 1966 | pmid = 5924645 }}{{cite journal | title = The ribonucleotide reductases - a unique group of metalloenzymes essential for cell-proliferation |author1 = Lammers, M. |author2 =Follmann, H. |journal = Struct. Bonding |year = 1983 |volume = 54 |pages = 27–91 |doi=10.1007/bfb0111318}} This enzyme catalyses the following chemical reaction

: 2'-deoxyribonucleoside triphosphate + thioredoxin disulfide + H₂O $\backslash rightleftharpoons$ ribonucleoside triphosphate + thioredoxin

Ribonucleoside-triphosphate reductase requires a cobamide coenzyme and ATP.