The immobilization of a thermophilic β-galactosidase on Sepabeads supports decreases product inhibition
2003; Elsevier BV; Volume: 33; Issue: 2-3 Linguagem: Inglês
10.1016/s0141-0229(03)00120-0
ISSN1879-0909
AutoresBenevides C. Pessela, César Mateo, Manuel Fuentes, Alejandro Vián, José L. Garcı́a, Alfonso V. Carrascosa, José M. Guisán, Roberto Fernandéz‐Lafuente,
Tópico(s)Enzyme Production and Characterization
ResumoThe β-galactosidase from Thermus sp. T2 (Htag-BgaA) is competitively inhibited by galactose (3.1 mM) and non-competitively inhibited by glucose (49.9 mM). These inhibitions were strongly reduced by immobilization on heterofunctional epoxy Sepabeads (boronate-epoxy-Sepabeads and chelate-epoxy-Sepabeads). The immobilized preparations displayed increased competitive inhibition constants (Ki) of galactose (boronate-epoxy-Sepabeads, 12.5 mM and chelate-epoxy-Sepabeads, 11.7 mM), whilst the enzyme KM (lactose) only doubled its value. A significant increment of the non-competitive constant was also found (by around a two-fold factor). These increments of the inhibition constants greatly impact on the industrial performance of the enzyme. Thus, while using soluble enzyme in the hydrolysis of 5% lactose, the reaction stopped at around 90% hydrolysis, both immobilized preparations to reached hydrolysis yields higher than 99%. These immobilized forms of β-galactosidase could be used in the total hydrolysis of lactose in milk or dairy whey even at 70 °C.
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