The structure of the immobilized Eversa Transform determines the activity/stability effects of the biocatalyst metallization

Abstract

In this paper, the human designed lipase Eversa Transform (ETL) has been immobilized on octyl agarose beads using 4 previously published protocols that provided biocatalysts with very different properties. Then, the biocatalysts were submitted to incubation with 7 different metal cations in Tris or buffer, with the objective of checking if the immobilized enzyme altered its properties after metallization and whether this modification has different qualitative and quantitative values when changing the immobilized enzyme protocol (that is, maintaining enzyme, support and enzyme orientation, only changing the enzyme structure). Enzyme activity versus nitro-phenol butyrate at different pH values using different buffers, enzyme activities versus this substrate and triacetin and R or S methyl mandelate and the enzyme stability under different conditions were studied. The results showed that the enzyme activity/ pH curve and specificity versus different substrates are drastically changed upon metallization, these changes depending on the presence of Tris or phosphate during mineralization and very interestingly, depending on the biocatalyst that is submitted to this treatment. The same treatment could increase the enzyme activity or stability for one biocatalyst while it could be negative for other biocatalysts.