Method for recovery of refined .alpha.-galactosidase

DETAILED DESCRIPTION OF THE INVENTION The methods heretofore suggested for the refinement of .
alpha.
-galactosidase suffer from various disadvantages such as poor recovery ratio, insufficient purity and complication of operation.
With a view to overcoming the difficulties, the inventors pursued various studies in search of a new method capable of advantageous recovery of .
alpha.
-galactosidase.
They developed a hypothesis that recovery of .
alpha.
-galactosidase of high purity ought to be obtained easily by causing .
alpha.
-galactosidase to be selectively adsorbed by means of an ion-exchange resin capable of specifically combining the .
alpha.
-galactosidase.
They tested ion-exchange resins to single out one which would qualify for the purpose.
They have, consequently, made a discovery that the weakly acidic cation-exchange resin specifically provides adsorption of the .
alpha.
-galactosidase in the presence of a buffer solution under stated conditions and permits desorption thereof by use of a buffer solution satisfying a specific requirement.
The present invention has been acomplished on the basis of this discovery.
As the .
alpha.
-galactosidase-containing liquid to be subjected to the treatment by the method of this invention, there can be used either the .
alpha.
-galactosidase-containing culture broth obtained by culturing any of the known .
alpha.
-galactosidase-producing microorganisms or the .
alpha.
-galactosidase-containing liquid obtained by extracting the .
alpha.
-galactosidase contained in frozen microorganic cells or dry microorganic cells.
The concentration of .
alpha.
-galactosidase in the broth or liquid makes little difference.
Particularly in the case of the .
alpha.
-galactosidase which is formed by the culture of molds, since the enzyme occurs for the most part within the cells of the molds, the .
alpha.
-galactosidase is extracted from the cells by physically or chemical treating the cells.
The extract consequently obtained is put to the treatment.
The ion-exchange resin to be used in the method of this invention is a weakly acidic cation-exchange resin of which examples are Amberlite IRC-50, IRC-75, IRC-84, CG-50 (products of Rohm and Hass company of the USA), Duolite CS-101, CS-100 (products of Diamond Alkali Co