Resumo

HERNANDEZ-MARTINEZ, R. et al. Purification and characterization of a thermostable alkaline protease produced by Yarrowia lipolytica. Rev. Mex. Ing. Quím [online]. 2011, vol.10, n.2, pp.333-341. ISSN 1665-2738.

Purification of the extracellular prote ase produced by Yarrowia lipolytica was realized in fo ur steps: ammonium sulfate precipitation, anionic exchange (2X) and gel filtration. The enzyme showed m olecular weight of 61.5 kDa (SDS-PAGE) and optimum activity at 52.4°C at pH 10-11. The thermal stability was modified in presence of Ca²⁺ (10 mM) providing an in crease of 73, 6 and 11% at 40, 50 and 60°C respectively. The thermodynamic parameters (enthalpy and entropy) indicate that the stability of the enzyme is not provided by non-covalent linkages. Furthermore the ion Ca²⁺ is important for thermodynamic stabilization of the enzymatic structure. The proteolytic activity was inhibited by PMSF; suggesting that the enzyme can be classify in the serine protease family. The results of thermodynamic stability allow classifying the protease studied as thermostable. The importance of the Ca²⁺ on the thermostability was corroborated; this is the first report on thermal stability and thermodynamic properties of proteases produced by Y. lipolytica.

Palavras-chave : Yarrowia lipolytica; protease; thermostable; thermodynamic stability.