Related Experiment Video
Updated: Jan 30, 2026

Characterization of Metabolic Status in Nonhuman Primates with the Intravenous Glucose Tolerance Test
Published on: November 13, 2016
A protease-resistant α-galactosidase characterized by relatively acid pH tolerance from the Shitake Mushroom
Lijing Xu1, Bowen Chen2, Xueran Geng1
1College of Food Science and Engineering, Shanxi Agricultural University, Taigu 030801, China; Collaborative Innovation Center of Advancing Quality and Efficiency of Loess Plateau Edible Fungi, Taigu 030801, China.
Abstract:
A monomeric α-galactosidase with a molecular weight of 64 kDa was purified from fresh fruiting bodies of Lentinula edodes. The purification protocol involved ion-exchange chromatography on DEAE-cellulose, CM-cellulose and Q-Sepharose and a final gel-filtration on Superdex 75. The purified α-galactosidase (LEGI) was identified by LC-MS/MS. It demonstrated the optimum pH of 5.0 and temperature optimum of 60 °C towards pNPGal. It was inhibited by Cd2+, Fe3+, Pb2+, Zn2+, Al3+, Hg2+, Cr2+, Ba2+. The LEGI activity was strongly abolished by the chemical modification N-bromosuccinimide (NBS) at 1 mM, while significantly enhanced by the thiol-reducing agents dithiothreitol (DTT). Moreover, LEGI showed strong resistance to protease pepsin, papain, acid protease and neutral protease. LEGI demonstrated hydrolysis towards melibiose (13.27%), raffinose (4.75%), stachyose (2.58%), locust bean gum (0.82%) and guar gum (1.29%). The Km values of LEGI for pNPGal, stachyose, raffinose, and melibiose were found to be 1.08, 17.24, 13.80 and 8.05 mM, respectively. Results suggest that LEGI demonstrates potential for elimination of indigestible oligosaccharides.
Related Concept Videos
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
α-Halogenation of Carboxylic Acid Derivatives: Overview
Phase II Reactions: Sulfation and Conjugation with α-Amino Acids
α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
Resistivity
Resistance

