E. coli K-12 Asparaginase-Based Asparagine Biosensor for Leukemia

Figures & data

Figure 1 Covalent binding of enzyme on nitrocellulose membrane. (1) Nitrocellulose membrane. (2) Enzyme + Phenol red on nitrocellulose membrane. (3) Enzyme + Phenol red + Asparagine (10⁻¹ M) → Purple Color.

Figure 2 Detection of asparagine levels of 10⁻¹⁰–10⁻¹ M (arranged in deceasing order of molar concentration in the figure) was not achieved on nitrocellulose membrane.

Table 1. The response time at various concentrations of asparagine solution on silicon gel plates

Asparagine concentration (M)	Response time
10^−1	5–10 sec
10^−5	1–2 min
10^−10	3–4 min

Figure 3 Immobilization of enzyme on silicon gel and reaction with varying concentration of asparagine (1) 10⁻¹ M (2) 10⁻⁵ M (3) 10⁻¹⁰ M.

Table 2. The response time for color change of beads

Concentration of asparagine (M)	Response time
10^−1	7 min 10 sec
10^−2	3 min 40 sec
10^−3	2 min 12 sec
10^−4	2 min 10 sec
10^−5	1 min 55 sec
10^−6	1 min 45 sec
10^−7	1 min 25 sec
10^−8	1 min 20 sec
10^−9	1 min 13 sec

Figure 4 Color of beads before and after the reaction.