Open AccessPurification and Properties of Alternanase, a Novel Endo‐α‐1,3‐α‐1,6‐ d ‐Glucanase
Author(s) -
Biely Peter,
Côté Gregory L.,
BurgessCassler Anthony
Publication year - 1994
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1994.tb20090.x
Subject(s) - leuconostoc mesenteroides , hydrolysis , isoelectric point , chemistry , enzyme , dextransucrase , molecular mass , biochemistry , glucan , sucrose , glucanase , polysaccharide , chromatography , bacteria , stereochemistry , biology , lactic acid , genetics
A newly isolated soil bacterium strain NRRL B‐21195, tentatively identified as a Bacillus species, was found to be a constitutive producer of a novel type of glycanase that hydrolyses in an endo‐fashion the polysaccharide alternan, an α‐1,3‐α‐1,6‐ d ‐glucan, referred to in the literature as B‐1355 dextran (fraction S), synthesized from sucrose by alternansucrase of Leuconostoc mesenteroides. The glycanase, named alternanase, has been purified to homogeneity from a cell‐free culture fluid of the bacillus grown in a liquid medium containing d ‐glucose, and has been characterized. The enzyme has a molecular mass of 110000 Da (SDS/PAGE) and an isoelectric point of approximately 4.0. Optimum activity occurs at pH 7 and at a temperature of 40°C. The enzyme is stable up to 50°C but loses activity rapidly at 60°C. Its action is inhibited by EDTA and stimulated by Ca 2+ . The enzyme requires, for its action, d ‐glucan chains in which α‐1,3‐linkages alternate with α‐1,6‐linkages; i.e., it is specific for alternan. Monitoring of alternan hydrolysis by determination of liberated reducing sugars pointed to an unusually low extent of hydrolysis and a low specific activity of the enzyme. As shown in the accompanying paper [Côté, G. L. & Biely, P. (1994) Eur. J. Biochem. 226 , 641–648] the reason for this finding is that the main hydrolytic products are non‐reducing, novel types of cyclic oligosaccharides.