Complex sentence: Nitrile hydratases are almost invariably co-expressed with an amidase, which converts the amide to the carboxylic acid, consequently it can sometimes be difficult to distinguish nitrilase activity from nitrile hydratase plus amidase activity.
Split into simpler sentences: Nitrile hydratases are almost invariably co-expressed with an amidase, which converts the amide to the carboxylic acid. Consequently, it can sometimes be difficult to distinguish nitrilase activity from nitrile hydratase plus amidase activity.