Catalytic effects of galactose oxidase on micelle-forming galactolipids.
Catalytic effects of galactose oxidase on the oxidation of beta-D-galactose-carrying lipids with an oligo-ethylene glycol spacer (number of ethylene glycol units (n)=1, 2, 3, 6, 9, 13, and 20) were examined. The affinity of galactose oxidase for the galactose residue in the amphiphile (estimated by the inverse of the Michaelis constant, K(m)) was much higher than those for free D-galactose and small beta-D-galactopyranosides, and dependent on the length of the ethylene glycol spacer. That is, both below and above the critical micellar concentration, the 1/K(m) values decreased with an increase in the n value. The effectiveness of the enzyme, which can be estimated by the k(cat)/K(m) value, showed the same tendency as the 1/K(m) value. These results could be attributed to the role of the nonpolar environment around the galactose residue in the binding by the enzyme. A significant enhancement of the enzymatic oxidation of galactose residue on the liposome surface was also observed.
Kitano
Hiromi
H
Department of Chemical and Biochemical Engineering, Toyama University, Toyama 930, Japan.
Ishino
Yukiko
Y
Al-Arifi
Ali Hamed
AH
D038983:Galactolipids / Q000378:metabolism*; D005692:Galactose Oxidase / Q000378:metabolism*; D007700:Kinetics; D008823:Micelles
D038983:Galactolipids; D008823:Micelles; D005692:Galactose Oxidase