Abstract

Active-site characterization of nuclease Stn á from Streptomyces thermonitrificans

Author(s): Sumedha S.Deshmukh

Chemical modification studies on purified nuclease Stn a revealed the involvement of Histidine, Carboxylate and Arginine in the active site of the enzyme. DNA, the substrate of the enzyme could protect the DEP (Histidine) and WRK (Carboxylate) inactivated enzyme but not Phenylglyoxal (Arginine) inactivated enzyme suggesting that histidine and carboxylate are present in substrate binding while arginine is in catalysis. Kinetics of inactivation indicated involvement of two histidines, two carboxylates in substrate binding while a single arginine in catalysis.