TY - JOUR
T1 - Characteristics of magnetic nanoparticles-bound YADH in water/AOT/isooctane microemulsions
AU - Liao, Min Hung
AU - Chen, Dong Hwang
N1 - Funding Information:
This work was performed under the auspices of the National Science Council of the Republic of China, to which the authors wish to express their thanks.
PY - 2002/9/13
Y1 - 2002/9/13
N2 - The yeast alcohol dehydrogenase (YADH) covalently bound onto Fe3O4 magnetic nanoparticles was performed in the NADH-containing water-in-oil microemulsions of water/AOT/isooctane. Both water and NADH were present in the aqueous phase of microemulsion solution and on particle surface. The ratio of the equilibrium water content on particle surface to that in the aqueous phase of microemulsion solution (i.e. aquaphilicty) was about 0.39 and independent of the molar ratio of water to AOT (ω0). The thickness of aqueous film on particle surface was estimated to be 3.1-5.7nm, increasing with increasing the ω0 value from 10 to 25. At a constant NADH amount, the concentration of NADH in the aqueous phase of microemulsion solution was not significantly affected by the ω0 value. In addition, the bound YADH showed excellent storage stability and good thermal stability in the microemulsion system. At 25°C for 700h and 75°C for 30min, its residual activities were 78 and 56%, respectively. The specific activity of bound YADH in the microemulsion system was 40% of that in aqueous solution. The maximum specific activity of bound YADH (Vmax), and the Michaelis constants for NADH (KmA) and 2-butanone (KmB) were determined to be 0.0306 μmol/minmg, 0.0589mM, and 0.1476M, respectively.
AB - The yeast alcohol dehydrogenase (YADH) covalently bound onto Fe3O4 magnetic nanoparticles was performed in the NADH-containing water-in-oil microemulsions of water/AOT/isooctane. Both water and NADH were present in the aqueous phase of microemulsion solution and on particle surface. The ratio of the equilibrium water content on particle surface to that in the aqueous phase of microemulsion solution (i.e. aquaphilicty) was about 0.39 and independent of the molar ratio of water to AOT (ω0). The thickness of aqueous film on particle surface was estimated to be 3.1-5.7nm, increasing with increasing the ω0 value from 10 to 25. At a constant NADH amount, the concentration of NADH in the aqueous phase of microemulsion solution was not significantly affected by the ω0 value. In addition, the bound YADH showed excellent storage stability and good thermal stability in the microemulsion system. At 25°C for 700h and 75°C for 30min, its residual activities were 78 and 56%, respectively. The specific activity of bound YADH in the microemulsion system was 40% of that in aqueous solution. The maximum specific activity of bound YADH (Vmax), and the Michaelis constants for NADH (KmA) and 2-butanone (KmB) were determined to be 0.0306 μmol/minmg, 0.0589mM, and 0.1476M, respectively.
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U2 - 10.1016/S1381-1177(02)00062-0
DO - 10.1016/S1381-1177(02)00062-0
M3 - Article
AN - SCOPUS:0037072990
VL - 18
SP - 81
EP - 87
JO - Journal of Molecular Catalysis - B Enzymatic
JF - Journal of Molecular Catalysis - B Enzymatic
SN - 1381-1177
IS - 1-3
ER -