β-galactosidases (EC 188.8.131.52) from mammals, fungi, plants and the bacteria
Xanthomonas manihotis are evolutionary related [1,2]. They belong to family 35
in the classification of glycosyl hydrolases [3,E1].
Mammalian β-galactosidase is a lysosomal enzyme (gene GLB1) which cleaves
the terminal galactose from gangliosides, glycoproteins, and
glycosaminoglycans and whose deficiency is the cause of the genetic disease
Gm(1) gangliosidosis (Morquio disease type B).
On of the best conserved regions in these enzymes contains a glutamic acid
residue which, on the basis of similarities with other families of glycosyl
hydrolases , probably acts as the proton donor in the catalytic mechanism.
We use this region as a signature pattern.
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