Preparation and analysis of corn stover leaf extracts containing recombinant CBH. Extracts were prepared at 16:1, 12:1, and 8:1 buffer-to-dry mass ratios. Extracts were prepared from non-transgenic corn stover leaf under the same conditions as negative controls. Cellulase activity was measured by monitoring the ability of extracts to release 4-methylumbelliferone (4-Mu) from 4-methylumbelliferyl-β-D-lactopyranoside (MUL) at pH 4.75 and 40°C, relative to a 4-Mu standard curve. Activity is presented as micromoles 4-Mu released per minute per milligram of protein and compared to the total MULase specific activity in Celluclast 1.5 L (C). All samples were analysed in triplicate, and error bars represent standard deviation.