Figure 2

Effects of pH on the activity of MgCl ₂ and bentonite to remove the TMV coat protein. Extracts were harvested in sodium acetate (pH 4–5) or tris (pH7-9) buffer depending on the desired pH range and were visualized using coomassie stained SDS-PAGE. Sample 1 shows the proteins in the initial extract and sample 2 represents the proteins after the extract is heated to 55°C and centrifuged. Sample 3 represents the extract after it was adjusted to its corresponding pH a) pH 4.0 and b) pH 9.0. Sample 3 extracts were centrifuged to remove additional precipitate and represented in sample 4. Samples 5–12 represent various temperature, bentonite, or MgCl₂ treatments of sample 4 performed in duplicate. MgCl₂ (M), bentonite (B), and bentonite & MgCl₂ (MB) Samples 5 & 6 were incubated overnight at 42°C. Samples 7 & 8 were incubated overnight at 42°C after treatment with 0.01 M MgCl₂. Samples 9 & 10 were incubated overnight at 4°C with the addition of 1 mg/mL bentonite. Samples 11 & 12 were incubated overnight at 4°C after the addition of 1 mg/mL bentonite & 0.01 M MgCl₂. Table: Densitometry readings of SDS-PAGE represented in Figure 2 with values from three additional gels representing additional pH values that were explored (pH 6.5, 7.0, 8.0). The shaded area represents an extract condition achieving greater than 80% purity of GRFT.