Cell cultures of Berberis beaniana (B. beaniana), which in this certain experiment are taken as an example, were harvested 10–12 days, contained large amounts of proto-berberines, mainly jatrorrhizine. These quaternary alkaloids have a strong inhibitory effect on the BBE, so they had to be removed. In order to eliminate most of these interfering cationic substances, the enzyme solution was treated first with carboxymethyl-Sepharose and subsequently with dextrancoated charcoal.
After that, the resulting solution was fractionated using standard procedures and generated, after isoelectric focusing, a single protein band in SDS gel electrophoresis. In the end, the obtained enzyme had been purified 450 times and contained 0.7% of the activity present in the crude extract at the beginning.