Novel transferase and amylase, process for producing the enzymes, use thereof, and gene coding for the same

Abstract

The invention provides a novel transferase that acts on a saccharide, as a substrate, composed of at least three sugar units wherein at least three glucose residues on the reducing end are linked α-1,4 so as to transfer the α-1,4 lingages to a α-1, α-1 linkages; a process for producing the transferase; a gene coding for the same; and a process for producing an oligosaccharide by using the same. Also provided are a novel amylase that has a principal activity of acting on a saccharide, as a substrate, composed of at least three sugar units wherein at least three sugar units on the reducing end side are glucose units and the linkage between the first and the second glucose units is α-1, α-1 while the linkage between the second and the third glucose units is α-1,4 so as to liberate α, α-trehalose by hydrolyzing the α-1,4 linkage and another activity of hydrolyzing the α-1,4 linkage within the molecular chain of the substrate and that liberates disaccharides and/or monosaccharides as the principal final products; a process for producing the amylase; a gene coding for the same; and a process for producing α, α-trehalose by using a combination of the transferase and the amylase.

1 - 7 . (canceled)  
     
     
         8 . A DNA fragment comprising a DNA sequence coding for a transferase, the transferase acting on a substrate saccharide, the substrate saccharide being composed of at least three sugar units wherein at least three glucose residues from the reducing end are α-1,4-linked, so as to transfer the first α-1,4 linkage from the reducing end into an α-1, α-1 linkage, and comprising an amino acid sequence as shown in SEQ ID No. 2 or 4, or a sequence equivalent to the amino acid sequence shown in SEQ ID No. 2 or 4 as long as it is able to transfer the first α-1,4 linkage from the reducing end of said saccharide into an α-1, α-1 linkage.  
     
     
         9 . The DNA fragment claimed in  claim 8  derived from an archaebacterium belonging to the order Sulfolobales.  
     
     
         10 . The DNA fragment claimed in  claim 9  derived from an archaebacterium belonging to the genus  Sulfolobus.    
     
     
         11 . The DNA fragment claimed in  claim 10  derived from  Sulfolobus solfacaricus  strain KM1 (FERM BP-4626).  
     
     
         12 . The DNA fragment claimed in  claim 10  derived from  Sulfolobus acidocaldarius  strain ATCC 33909.  
     
     
         13 . A DNA fragment which hybridizes with the base sequence from the 335 th  base to the 2518 th  base of the base sequence shown in Sequence No. 1 at 40° C. under an ionic strength of 5×SSC, and which codes for a transferase acting on a substrate saccharide, the substrate saccharide being composed of at least three sugar units, wherein at least three glucose residues from the reducing end are α-1,4-linked, so as to transfer the first α-1,4 linkage from the reducing end into an α-1, α-1 linkage; and a DNA fragment which codes for the amino acid sequence encoded by the foregoing DNA fragment.  
     
     
         14 . A DNA fragment which hybridizes with the base sequence from the 1880 th  base to the 2257 th  base of the base sequence shown in Sequence No. 1 at 60° C. under an ionic strength of 6×SSPE, and which codes for a transferase acting on a substrate saccharide, the substrate saccharide being composed of at least three sugar units wherein at least three glucose residues from the reducing end are α-1,4-linked, so as to transfer the first α-1,4 linkage from the reducing end into an α-1, α-1 linkage; and a DNA fragment which codes for the amino acid sequence encoded by the foregoing DNA fragment.