The Study of the Structure and Activity of the Bovine Pancreatic Ribonuclease A in the Presence of Allopurinol

Bovine pancreatic ribonuclease A is an endoribonuclease. This enzyme cut chemical phosphodiesteric bond in a single stranded RNA with two steps reaction. The first step of this enzymatic reaction is transphosphorylation and the second step is hydrolysis. Allopurinol is one the structural isomer of hypoxanthine (one of the natural purine) that inhibits xanthine oxidase so reduce production of uric acid and is one of the current drugs ingout treatment. This drug has a nucleotidic structure so may has an effect on the structure and activity of ribonuclease A. In attention to key role of RNase A in degredation of RAN for maintanace of cellular system equilibrium, it is necessarytoinvestigate the effect of different biological molecules and drugs on the activity of RNase A. So in this project we investigated the effect of different concentration of allopurinol on the activity and structure of bovine pancreatic ribonuclease A. At first saturation curve of enzyme in the presence of cCMP is drawn. Then effect of allopurinol in the range of 0-1, 0-5 mM on the maximum rate of enzyme is investigated and saturation curve of enzyme in the presence of allopurinol is drawn. The results show that drug reduces activity of this enzyme in tested concentrations. Structural studies with ligand binding and CD prove the considerable change in enzyme. In general, we can say that allopurinol may inhibit activity of RNase A.