Different charge forms of aromatic-l-amino-acid decar☐ylase

The isoelectric points (pI) of aromatic-l-amino-acid decar☐ylase (AADC) from two species, rat and cow, were determined by chromatofocusing. The enzyme from both rat brain and adrenal has a pI of 5.5, while the bovine adrenal enzyme has a different pI of 5.0. Thus, the variation of isoelectric point for AADC is limited to species differences but not tissue differences.