β-Galactosidase isolated from Ranunculus arvensis seeds to synthesize trisaccharide: Kinetics and thermodynamic properties

Abstract

β-Galactosidase was isolated from Ranunculus arvensis seeds using DEAE-cellulose, Sephadex G-100, and Con A sepharose-4B chromatography. The enzyme was purified to electrophoretic homogeneity with a specific activity of 50 U/mg of protein and a yield of 7.1%. The molecular mass of the isolated β-galactosidase, as estimated by SDS-PAGE, was 18 kDa, indicating that it was a monomeric form The purified β-galactosidase has a glycoproteinic nature when applied to Con-A-Sepharose-4B chromatography. An activation energy (Ea) of 11 kcal/mol of lactose, pH 5.0, and 50 °C were found to be the optimum parameters to purify β-galactosidase from R. arvensis seeds. The residual activity test was carried at 55–75 °C, allowing calculating the half-lives of 533–48 min, enthalpy (ΔH° = 110.38–110.21 kJ/mol), free energy (ΔG° = 109.88–109.77 kJ/mol), and entropy (ΔS° = 1.52–1.26 J/mol·K). The β-galactosidase produced from this species is better than the previously described enzyme due to its kinetic and thermodynamic properties, and it could be used in various industrial applications. Purified β-galactosidase, when incubated with high lactose concentration, showed transgalactosylation activity, leading to trisaccharides as a major product of total galactooligosaccharide (GOS). Therefore, the purified β-galactosidase could be used as a potential alternative in the food industry and would be further explained for trisaccharide synthesis.