Wells were loaded with 10 mg of EE protein from a single by-product type, commercial papain (SIGMA Cat.#P5306) or a broad-range molecular weight standard (BIORAD, USA, Cat. #1610318) containing myosin (202.81 kDa); b-galactosidase (115.55 kDa); bovine serum albumin (98.22 kDa); ovoalbumin (51.36 kDa); carbonic anhydrase (37.24 kDa); soybean trypsin inhibitor (29.0 kDa); lysozyme (19.74 kDa); and aprotinin (6.65 kDa).