Saccharide oxidase, and production method for same and use of same

Abstract

A protein having a novel saccharide oxidase activity capable of being subjected to various uses is provided. The present invention provides a protein having the following physicochemical characteristics: (1) effect: oxidizing a saccharide to produce a saccharic acid; (2) substrate specificity: acting on glucose, maltotriose, maltose, galactose, maltotetraose, lactose, and cellobiose; and, (3) [Km value of glucose]/[Km value of maltose]≦1.

1 . A protein having the following physicochemical characteristics:
 (1) effect: oxidizing a saccharide to a saccharic acid;   (2) substrate specificity: acting on glucose, maltotriose, maltose, galactose, maltotetraose, lactose, and cellobiose; and,   (3) [Km value of glucose]/[Km value of maltose]≦1.   
     
     
         2 . The protein according to  claim 1  wherein 0.4 [Km value of glucose]/[Km value of maltose]≦1. 
     
     
         3 . A protein having the following physicochemical characteristics:
 (1) effect: oxidizing a saccharide to produce a saccharic acid;   (2) substrate specificity: acting on glucose, maltotriose, maltose, galactose, maltotetraose, lactose, and cellobiose; and,   (3) molecular weight: about 63 kDa (measurement by SDS-PAGE method).   
     
     
         4 . The protein according to  claim 3  wherein [Km value of glucose]/[Km value of maltose]≦1. 
     
     
         5 . The protein according to  claim 4  wherein 0.4≦[Km value of glucose]/[Km value of maltose]≦1. 
     
     
         6 - 17 . (canceled) 
     
     
         18 . A protein described in the following (a), (b), or (c):
 (a) a protein consisting of the amino acid sequence represented by SEQ.ID.NO:10;   (b) a protein consisting of an amino acid sequence resulting from deletion, substitution, and/or addition of one to several amino acids in the amino acid sequence represented by SEQ.ID.NO:10 and having a saccharide oxidase activity;   (c) a protein consisting of an amino acid sequence having a homology of 90% or more with the amino acid sequence represented by SEQ.ID.NO:10 and having a saccharide oxidase activity.   
     
     
         19 . A gene encoding the protein according to  claim 18 . 
     
     
         20 - 21 . (canceled) 
     
     
         22 . A recombinant vector containing the gene according to  claim 19 . 
     
     
         23 . A transformant resulting from transformation of a host cell with the recombinant vector according to  claim 22 . 
     
     
         24 . A method for producing a protein by collecting the protein according to any one of  claims 1 ,  3  and  18  from a culture obtained by culturing a microorganism having an ability of producing the protein according to any one of  claims 1 ,  3  and  18  in a nutrient medium. 
     
     
         25 . A method for producing a protein by culturing the transformant according to  claim 23  in a culture medium and collecting a protein having a saccharide oxidase activity from the culture. 
     
     
         26 . A method for producing a saccharic acid comprising producing the saccharic acid from a saccharide using the protein according to any one of  claims 1 ,  3  and  18 . 
     
     
         27 . Use of the protein according to any one of  claims 1 ,  3  and  18  for oxidizing a saccharide in a food product. 
     
     
         28 . A method for desugaring egg white comprising at least using the protein according to  claim 27 . 
     
     
         29 . A method for producing a desugared egg white using the desugaring method according to  claim 28 . 
     
     
         30 . A method for improving the quality of a bread and/or the physical property of a dough comprising at least using the protein according to  claim 27 . 
     
     
         31 . A method for producing a bread comprising using the improvement method according to  claim 30 . 
     
     
         32 . A method for producing lactobionic acid comprising at least using the protein according to  claim 27 .