What is the purine repressor?
The purine repressor (PurR) is a DNA-binding protein involved in the process of transcription. Its name indicates its function: it represses the synthesis of purines. Characterization of PurR has been accomplished primarily by studying its function in bacteria, mainly Escherichia coli. Little is presently known about purine gene expression in humans and other eukaryotes. [top] Why is this important? Purine nucleotides are important in cellular metabolism. Cells require them to serve as the monomeric substrates for the synthesis of polynucleotides and enzymatic cofactors, to carry the high-energy phosphate bonds necessary to catalyze enzymatic reactions, and to function as second messengers within a cell. Purine nucleotides play an important role in many biochemical processes. ATP is the cell’s main energy source. Adenine nucleotides serve as the components of coenzymes: Coenzyme A, FAD and NAD+. GTP is needed for activation of biochemical processes. In addition, the nucleotides serve a
