The unique cold-adapted extracellular subtilase from psychrophilic yeast Leucosporidium antarcticum

The extracellular subtilase synthesized by a strain of L. antarcticum isolated from the Admiralty Bay waters (depth of 200 m) was purified to homogeneity by means of 3-step column chromatography and characterized. The enzyme appeared to be kinetically and thermodynamically adapted to cold (Topt 25 °C, poor thermostability, high catalytic efficiency at 5–25 °C, low values of ΔG∗, ΔH∗, ΔS∗ and Ea). The sequence of 35 N-terminal amino acid residues of the L. antarcticum proteinase shows 31 and 37% homology with that of proteinase K and A. oligospora subtilase, respectively, thus indicating that the L. antarcticum serine proteinase belongs to the subfamily C clan SB. It is the first psychrophilic yeast subtilase in this subfamily.