Alpha-galactosidase catalyzes the hydrolysis of simple and complex sugars
containing alpha -1,4 galactosidic linkages and alpha-1,6 linked terminal galactosyl
Due to its widespread presence and functionality in animals, plants and
microorganisms, alpha-galactosidase is very useful commercially and medically.
galactosidase was purified from a culture of brewer’s yeast,
through performing a batch purification from an ion-exchange resin (DEAE-sephadex), a
NaCl gradient elution from a DEAE sephadex column, dialysis, and gel filtration, which
also aided in determining the molecular weight of the enzyme.
The initial specific
activity of the enzyme was 0.127 units/mg (μmol/min/mg) and the final specific activity
after purification was 1.22 units/mg showing that the enzyme was purified by a factor of
Analysis of the purified α- galactosidase was performed through sodium dodecyl
sulfate (SDS) polyacrylamide gel electrophoresis (SDS-PAGE) and native gel
electrophoresis to estimate molecular weight of the enzyme, which was found to be 71.98
By exposing the enzyme to various temperatures and different pH levels, an
optimal temperature, 55
C, and pH, 5, for alpha-galactosidase enzymatic activity were
The enzyme was also subjected to various concentrations of the substrate p-
nitrophenyl –α –D-galactoside
(pNPG) and various inhibitors in order to analyze their
effects on α- galactosidase reaction rate.
Alpha-galactosidase catalyzes the hydrolysis of simple and complex
oligosaccharides and polysaccharides containing alpha-1,4 galactosidic linkages and
alpha-1,6 linked terminal galactosyl groups. Since these linkages are widely distributed
among microorganisms, plants, and mammals, such as humans, this enzyme is of great
biochemical importance and commercial value.
α-galactosidase plays an important role
in the production of beet sugar since it acts as the enzyme that catalyzes the hydrolysis of
raffinose, which interferes with the crystallization of sucrose from sugar beet molasses.
Removal of the galactose from the raffinose promotes the forming of the beet sugar
(crystallization). (Khire, et al. 1999).
Studies of α-galactosidase have also shown that it is also of great medical
importance since its absence leads to Fabry’s disease, an inherited, “X-linked,”
This enzymatic defect leads to the systematic accumulation of
glycosphingolipids in endothelium cells, vascular smooth muscle cells, myocardium,
fibroblasts, perineurium, and other cells in multiple organs.
The only specific therapy
available for Fabry’s disease is intravenous infusion of recombinant human alpha-
galactosidase. (Pleasure, 2005 & Mohanraj, et al, 2002).