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264 Benčina et al.
Table 2
Long-Term Stability of Deoxyribonuclease Enzyme Reactor Stored Either in
Water or in Buffer at 4°C.
Days Biological activity (dA 260nm /min) % initial activity
Water
0 0.041 100
2 0.023 57
4 0.020 49
8 0.011 26
Buffer
0 0.118 100
1 0.105 89
2 0.103 87
3 0.098 83
6 0.089 75
8 0.089 75
13 0.034 29
21 0.021 18
31 0.012 10
Biological activity was determined as described in Subheading 3.3.2. DNA concentration
was 0.02 g/l in 40 mM Tris buffer, pH 8, 1 mM MgCl 2 , 1 mM CaCl 2 and detection wavelength
260 nm.
6
m DNase 0,8 mg
1/V (1/(dA 260nm /min))
5
4
3
2
1
0
-10 30 70 110 150 190 230
1/S (1/(g/1))
Fig. 3. Double reciprocal (1/v versus 1/[S]) Lineweaver–Burk plot of immobilized
deoxyribonuclease (DNase) (9). The intercept with x-axis represents –
1/K m and intercept with y-axis represents 1/v max . The biological activity of
immobilized DNase is determined by on-line frontal analysis as described in
Subheading 3.3.2. Enzyme reactor: CIM disk, median pore size 6 μm. Chromatographic
conditions: flow rates 0.1–10 ml/min, calf thymus DNA 0.006–0.08 g/l
in 40 mM Tris-HCl buffer, pH 8, 1 mM MgCl 2 , 1 mM CaCl 2 , detection wavelength 260 nm.