Effects of glucose, ethanol, Hg(II) and Cu(II) on almond beta-glucosidase.
The kinetic parameters of almond beta-glucosidase (beta-D-glucoside glucohydrolase; EC 3.2.1.21), using pNGP as substrate were kM = 2.24 +/- 0.11 mM and Vmax 588 +/- 25.1 U/mg protein. Only Hg(II) and Cu(II) showed irreversible inactivation of the enzyme. However, when these metals were present in the reaction system the inhibition effects were consistent with a mixed-type inhibition pattern (Cu(II) ki: 5.08 mM and Hg(II) ki: 0.07 mM). The glucose kinetic effect was also consistent with a mixed-type inhibition (ki = 406 mM) pattern with pNGP as varied substrate. Ethanol displayed the kinetic pattern of competitive inhibition (ki = 640 mM).
Romeu
A
A
University of Rovira i Virgili, Department of Biochemistry and Biotechnology, Tarragona, Spain.
Montero
M A
MA
Ruiz
J A
JA
De María
M J
MJ
Jimenez
J A
JA
Rojas
A
A
Arola
L
L
D000595:Amino Acid Sequence; D001665:Binding Sites; D003300:Copper / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D005960:Glucosides / Q000378:metabolism; D007700:Kinetics; D008628:Mercury / Q000494:pharmacology; D008969:Molecular Sequence Data; D009754:Nuts / Q000201:enzymology*; D016415:Sequence Alignment; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D005960:Glucosides; C025193:4-nitrophenyl beta-D-glucoside; D000431:Ethanol; D003300:Copper; D001617:beta-Glucosidase; D008628:Mercury; D005947:Glucose