Open AccessPurification and some properties of a thermostable acidic endo‐β‐1,4‐ d ‐mannanase from Sclerotium ( Athelia ) rolfsii
Author(s) -
Sachslehner Alois,
Haltrich Dietmar
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13712.x
Subject(s) - sclerotium , isoelectric point , chemistry , ammonium sulfate precipitation , size exclusion chromatography , biochemistry , ion chromatography , chromatography , molecular mass , hydrolysis , ammonium , isoelectric focusing , mannan , enzyme assay , enzyme , polysaccharide , biology , botany , organic chemistry
The phytopathogenic fungus Sclerotium ( Athelia ) rolfsii forms one major endo‐β‐1,4‐ d ‐mannanase (EC 3.2.1.78) under non‐induced and derepressed conditions, i.e. after depletion of glucose which was used as the only carbohydrate substrate for its cultivation. This mannanase was purified to electrophoretic homogeneity by ammonium sulfate precipitation, hydrophobic interaction chromatography, anion exchange chromatography and gel filtration. The enzyme is a glycoprotein with a molecular mass of 46.5±2 kDa (SDS‐PAGE), an isoelectric point of 2.75, and a pH optimum of 3.0–3.5. The enzyme is especially stable in the acidic region with an exceptional half‐life of activity of 41 days at pH 4.5 and 50°C. It exerts activity on β‐1,4‐mannan from ivory nut, which is hydrolyzed mainly to mannobiose and mannotriose, as well as on glucomannan, galactomannan, galactoglucomannan, and mannooligosaccharides not smaller than mannotetraose. The main end‐products mannotriose and to a lesser extent mannobiose inhibit its activity moderately.