dGTP

Deoxyguanosine triphosphate (dGTP) is one of the four deoxyribonucleoside triphosphates that serve as substrates for DNA synthesis. It consists of the deoxyribose sugar, the guanine base, and three phosphate groups. In cells, dGTP is part of the intracellular deoxynucleotide triphosphate (dNTP) pool that DNA polymerases draw upon during replication and repair. During DNA synthesis, dGTP is incorporated into the growing DNA strand opposite cytosine, releasing pyrophosphate.

Biosynthesis and regulation of dGTP are linked to the overall control of dNTP pools. The primary source is ribonucleotide reductase, which reduces GDP to dGDP, followed by phosphorylation to dGTP. The four dNTP pools are tightly balanced; imbalances can elevate mutation rates or stall replication. Interconversion and turnover involve deoxynucleoside kinases, nucleotidases, and related enzymes, ensuring supply according to cellular demand and cell cycle stage. In mitochondria, similar enzymes contribute to the local dNTP pool required for mitochondrial DNA replication and repair.

Clinical and laboratory relevance varies with context. In molecular biology, dGTP is a standard substrate for DNA polymerases in techniques such as PCR, cloning, and sequencing. In research and therapeutics, deviations in dGTP levels can accompany metabolic stress or exposure to nucleoside analogs, and imbalanced pools are associated with genomic instability if replication is perturbed.