Soluble protein
was determined by the protein reagent [0.01% (w/v) Coomassie
Brilliant Blue G-250 (Fluka Chemicals, Gillingham, UK), 4.7% (w/
v) ethanol, 8.5% (w/v) phosphoric acid]. The protein standard was
bovine serum albumin, and the absorbance was measured at
595 nm