Proteins having acquired A-galactosidase activity
The present invention provides a pharmaceutical composition comprising a protein having α-galactosidase activity for treating Fabry disease, which causes no allergic side effect, which is highly stable in blood (plasma) and which can readily be taken up by a cell of an affected organ. The pharmaceutical composition for treating Fabry disease of the invention comprises, for example, a protein which acquires an α-galactosidase activity through alteration of the structure of the active site of wild-type human α-N-acetylgalactosaminidase.
1. An isolated protein comprising a variant of SEQ ID NO: 6 having α-galactosidase activity, said variant selected from:
(i) the variant of SEQ ID NO: 6 consisting of a substitution of serine 202 by a different amino acid;
(ii) the variant of SEQ ID NO: 6 consisting of a substitution of alanine 205 by a different amino acid;
(iii) a variant of SEQ ID NO: 6 consisting of a substitution of serine 202 by a different amino acid and a substitution of serine 205 by a different amino acid; and
(iv) a variant of SEQ ID NO: 6 consisting of a substitution of serine 202 by a different amino acid and/or a substitution of serine 205 by a different amino acid and wherein one to ten additional amino acids are deleted, substituted or added.
2. The isolated protein according to claim 1 , wherein serine 202 is substituted with glutamic acid or aspartic acid.
3. The isolated protein according to claim 1 , wherein alanine 205 is substituted with leucine, valine, isoleucine, phenylalanine, or methionine.
4. The isolated protein according to claim 1 , wherein serine 202 is substituted with glutamic acid and alanine 205 is substituted with leucine.