Purification and characterization of the alpha-glucuronidase from Thermoanaerobacterium sp. strain JW/SL-YS485, an important enzyme for the utilization of substituted xylans
1995
Shao, W. | Obi, S.K.C. | Puls, J. | Wiegel, J.
A cell-associated alpha-glucuronidase was purified to gel electrophoretic homogeneity from the thermophilic anaerobic bacterium Thermoanaerobacterium sp. strain JW/SL-YS485. This enzyme had a pI of 4.65, a molecular weight of 130,000, and two subunits; the molecular weight of each subunit was 74,000. The enzyme exhibited the highest level of activity at pH 5.4 and 60 degrees C, as determined by a 5-min assay. The Km and kcat values of the enzyme for 4-methylglucuronosyl xylobiose were 0.76 mM and 1,083 IU/micromoles, respectively. The Arrhenius energy was 26.4 kJ/mol. The specific activities of the enzyme with 4-O-methylglucuronosyl xylobiose, 4-O-methylglucuronosyl xylotriose, and 4-O-methylglucuronosyl xylotetraose were 8.4, 4.8, and 3.9 IU/mg, respectively. The purified alpha-glucuronidase and a beta-xylosidase purified from the same organism interacted synergistically to hydrolyze 4-methylglucuronosyl xylotetraose.
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