Glucosidase II from control and ethanol-treated rats. Purification and properties.
Liver glucosidase II from control and ethanol-treated rats was purified and its physical and catalytic properties studied. No significant variation was found in the purification and properties of the enzyme from either source (ethanol-treated and control rats), except for activity after storage. Glucosidase II was purified to electrophoretic homogeneity from liver microsomes by solubilization, protamine sulphate precipitation, and anion exchange (DEAE-Sephacel) and affinity (Con A-Sepharose-4B) chromatographies. The native enzyme molecule is a tetramer (Mr 425 +/- 10 kDa) with identical subunits (Mr 106 +/- 3 kDa). Km values, determined at pH 6.8 for the p-nitrophenyl-glucosidase activity of glucosidase II from control and ethanol-treated rats, were 1.20 +/- 0.12 and 1.14 +/- 0.13 mM, respectively. The Arrhenius plot was linear, and the value for the apparent activation energy, calculated from this plot, was 56.64 kJ/mol. The p-nitrophenyl-glucosidase activity of glucosidase II from control and ethanol-treated rats was inhibited to the same extent by NH4+, by the divalent cations Ca2+ and Mg2+, and by methanol, ethanol, 2-propanol, n-propanol, isobutanol and n-butanol.
Santa-Cecilia
A
A
Departamento de Bioquímica y Biología Molecular, Universidad de Léón, Spain.
Alonso
J M
JM
Calvo
P
P
D000437:Alcoholism / Q000201:enzymology; D000818:Animals; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D000431:Ethanol / Q000494:pharmacology*; D007700:Kinetics; D046911:Macromolecular Substances; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013816:Thermodynamics; D000520:alpha-Glucosidases / Q000302:isolation & purification* / Q000378:metabolism
D046911:Macromolecular Substances; D000431:Ethanol; C034251:4-nitrophenyl-alpha-glucosidase; D000520:alpha-Glucosidases