Galactosidases galactomannans

Gleditsia ferox galactomannan a-D-Galactosidase-treated locust-bean 3.90 1 1.13 1... 

Galactomannans have been treated with a-D-galactosidase, and the extent of removal of D-galactose has varied considerably.88,101 105 With enzymes from lucerne104 and guar seed,105 essentially all of the D-galactosyl groups... 

According to Reese and Shibata,221 the biodegradative hydrolysis of galactomannan requires at least three different enzymes, namely, a-D-galactosidase, endo-/3-D-mannanase, and j3-D-mannosidase. In addition to these enzymes, there is also a report222 of a phosphorylase, identified as oligo-j8-D-mannosyl-(l— 4)-phosphorylase, which may take part in the degradation. These enzymes will now be discussed in detail. 

Hylin and Sawai219 reported that the crystalline depolymerase from Leucaena leucocephala converts the galactomannan from the same source into D-galactose and D-mannose. Hence, it is most likely that the enzyme preparation contained /3-D-mannosidase activity, in addition to a-D-galactosidase and /3-D-mannanase activities. 

Although chemical techniques have provided a considerable amount of dais on the structure of galactomannans, it has required the use of highly purified enzymes to determine the distribution of the side chains. Studies using a-D-galactosidases have indicated that the galactomannans from Gleditsia ferox and locust bean have a different distribution of a-D-Ga p residues (Courtois and Le Dizet, 1966). 

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