Total Protein Extraction and Analysis

Total protein was measured using the Bradford assay according to the supplier’s (Invitrogen¹) instructions. Protein was extracted from root and leaf tissue of cassava using 50 mM Tris-HCl (pH 8.5), 5 mM dithiothreitol and 1 mM EDTA. Extraction buffer was used at a ratio of 5 mL of buffer per gram fresh tissue. Leaves were ground in liquid nitrogen to a fine powder before adding the buffer. Tuberous roots were blended together in the buffer in the Magic Bullet MB1001 blender (Homeland Houseware LLC) for 30 s at 4°C. The ground extract was passed through four layers of cheesecloth and centrifuged at 21000 g for 10 min. The supernatant was used as the crude extract and measured for protein using the Bradford reagent with bovine serum albumin (BSA) as the standard.