Stabilization by Cations of Hydrophobically Immobilized Lipases

FERNANDEZ-LOPEZ, L.; BARTOLOME-CABRERO, R.; RUEDA, N.; RODRÍGUEZ, M. D.; ALBUQUERQUE, T. L.; DOS SANTOS, J. C. S.; BARBOSA, O.; FERNANDEZ-LAFUENTE, R

Istanbul

Congreso; 11th International Conference on Protein Stabilisation; 2016

Background: Lipases immobilized on hydrophobic supports have stabilized their open form, while if they are covalentlyimmobilized, the lid still have certain mobility. Recently, glyoxyl-octyl agarose has been presented as a very suitable method toachieve suitable biocatalysts of lipases, but it has some drawbacks, like the necessity of lipase incubation at alkaline pH valuesto get covalent attachment, a condition no adequate for all lipases.Materials: Octyl-agarose, BrCN-agarose and glyoxyl-octyl-agarose have been used as supports. CRL, RML, TML, CALA, Lecitasehave been used as enzymes.Results and Discussion: TML, CALA and Lecitase are not stabilized in any of the immobilized forms or in the soluble form byany assayed cation. RML and CRL, but only after immobilization on octyl-agarose beads, are stabilized at pH 5 and 7 by 5 mMof Ca2+ or Mn2+. Using Tris buffer, 5 mM of both salts were solubilized at pH 10. Now, only octyl-RML was stabilized by Ca2+. Thishas permitted to prepare glyoxyl-octyl-RML preparations with improved stability and activity.Conclusion: Immobilization may tune the positive effects of some additives on enzyme properties.5 mM of some cations areuseful to improve enzyme operational stability or the preparation of biocatalyst under inactivating conditions.