β(1→4)-Galactosidase, positionally specific from Streptococcus pneumoniae

β-Galactosidase is present in bacteria, fungi, yeast and animal organs. It is also found in fruits, such as apples, almonds and apricots. β-Galactosidase is a tetramer and is made up of four polypeptide chains consisting of amino acids that assemble to form five structural domains. The domains are jelly roll barrel, a central domain that serves as an active site and the remaining domains are composed of β-sandwich and fibronectin.

β(1→4)-Galactosidase, positionally specific from Streptococcus pneumonia has been used:

• as a position-specific enzyme to study its effects in the terminal galactosylation with protective efficacy of glycosphingolipid (GSPL) in mice.
• for the digestion of radioactive oligosaccharides.
• as a position-specific enzymeto study its effects on the virulence profile of avirulent Leishmania donovani clone (A-LD).

β-Galactosidase plays a role in hydrolyzing the D-galactosyl moieties in oligosaccharides, polymers and secondary metabolites. It is widely applicable in the dairy industry to remove lactose from milk and dairy products for the benefit of lactose-intolerant individuals. β-Galactosidase is also applicable in the food industry to improve the sweetness, flavor and solubility.

Solution in 20 mM Tris-HCl, pH 7.5, 25 mM NaCl

One unit will hydrolyze 1 μmole of p-nitrophenyl β-D-galactopyranoside per min at pH 5.0 at 37 °C.