A cold-adapted extracellular serine proteinase of the yeast Leucosporidium antarcticum
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- Turkiewicz, M., Pazgier, M., Kalinowska, H. et al. Extremophiles (2003) 7: 435. doi:10.1007/s00792-003-0340-9
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An extracellular serine proteinase, lap2, from the psychrophilic antarctic yeast Leucosporidium antarcticum 171 was purified to homogeneity and characterized. The enzyme is a glycoprotein with a molecular mass of 34.4 kDa and an isoelectric point of pH 5.62. The proteinase is halotolerant, and its activity and stability are dependent neither on Ca2+ nor on other metal ions. Lap2 is a true psychrophilic enzyme because of low optimal temperature (25°C), poor thermal stability, relatively small values of free energy, enthalpy and entropy of activation, and high catalytic efficiency at 0–25°C. The 35 N-terminal amino acid residues of lap2 have homology with subtilases of the proteinase K subfamily (clan SB, family S8, subfamily C). The proteinase lap2 is the first psychrophilic subtilase in this family.