Aspergillus Niger thermostable Cytosine deaminase-dextran conjugates with enhanced structure stability, proteolytic resistance, and Antiproliferative activity

Table 4 Thermal kinetic parameters of A.niger free and Dextran-CDA conjugates

Temp.(°C)	Free- CDA		Dextran- CDA		Stabilizing Ratio (%)
Temp.(°C)	T_1/2 (h)*	Kr (min) **	T_1/2 (h)	Kr (min)	Stabilizing Ratio (%)
30	32.51	0.152	48.63	0.043	1.50
37	29.38	0.155	39.27	0.048	1.34
45	12.95	0.200	13.92	0.063	1.07
50	9.27	0.250	12.54	0.098	1.35
55	8.61	0.260	11.07	0.134	1.28

*Half-life time (T_1/2) was expressed by time, which the enzyme retains 50% of its initial activity by preheating without substrate at each temperature degree
** Thermal denaturation rate (K_r) was expressed by the logarithmic decreasing of enzyme activity with the time at each temperature. It described by the first-ordered kinetic model; ln (At/A0) = − K_r T_m where A₀ and at are the specific activity of CDA at zero and t time

ISSN: 1471-2180