Green solvents made from glycerol change the classical regioselectivity of Biolacta No 5 β-galactosidase, from β(1→4) to β(1→6) linkages when a 2 M concentration was used. In order to explain these results, the non-proteic compounds present in the Biolacta preparation were separated by precipitation with ammonium sulfate and the remaining protein extract was used to set reactions with appropriate organic solvents to find that the regioselectivity towards the β(1→6) isomer is retained. According to proteomic analysis, a 98% homology between Streptococcus pneumoniae and Biolacta β-galactosidase preparation was found. With these data, molecular modelling was done which predicts a tridimensional interaction in the enzyme active site with the donor (GlcNAc) and the water-solvent mixture which explains this phenomenon.
