|Biely, Peter - SLOVAK ACAD OF SCIENCES|
Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2000
Publication Date: N/A
Technical Abstract: Alternanase is an enzyme which endo-hydrolytically cleaves the alpha- (1-3), alpha-(1-6)-linked D-glucan alternan. Enzymatic hydrolysis of alternan produces a series of oligosaccharides, the main product being a cyclic tetrasaccharide of D-glucose with alternating alpha-(1-3) and alpha-(1-6) linkages. An improved method for larger-scale preparation of the enzyme will be described. We also have developed an aqueous-based system for the preparation of gram-quantities of the cyclic tetrasaccharide. This protocol involves removal of reducing saccharides by ion-exchange at high pH, followed by gel-filtration chromatography. These improved methods have allowed us to prepare sufficient material for further studies, including inhibition studies. We found that alternanase is inhibited by its own products. Isomaltose exhibited a Ki of 15 mM, and the cyclic tetrasaccharide exhibited a Ki of 4 mM. Furthermore, the enzyme is also capable of hydrolyzing the cyclic tetramer at relatively slow rates. Studies on the action of alternanase on several oligosaccharide analogues of alternan will also be described.