puriinivälittäjät
Puriinivälittäjät, also known as purine nucleoside phosphorylases (PNPs), are enzymes that play a crucial role in purine metabolism. They catalyze the reversible phosphorolytic cleavage of the glycosidic bond in purine nucleosides, such as inosine and guanosine, to yield the corresponding free purine base and ribose-1-phosphate. This process is a key step in both purine salvage pathways, where pre-existing purine bases are recycled to form new nucleotides, and purine degradation pathways, where purines are broken down for excretion.
PNPs are widely distributed in nature, found in bacteria, fungi, plants, and animals. In mammals, the enzyme
The activity of puriinivälittäjät can be influenced by various factors, including substrate concentration, pH, and the