Isolation from Nocardioides sp. strain CT16, purification, and characterization of a deoxycytidine deaminase extremely thermostable in the presence of D,L-dithiothreitol.

A deoxycytidine deaminase that was extremely thermostable in the presence of dithiothreitol was found in a mesophilic bacterium isolated from soil. The bacterium was classified as a Nocardioides sp. The enzyme was purified to a homogeneous protein by treatment at 100 degrees C, ammonium sulfate precipitation, and chromatography on DEAE-Toyopearl, hydroxyapatite, and then Sephacryl S-100.