Purification and properties of aromatic l-amino acid decarboxylase from liver of skipjack tuna (Katsuwonus pelamis, Teleostei: Scombridae)

Abstract

Aromatic l-amino acid decarboxylase (AADC; EC 4.1.1.28) was extracted from skipjack (Katsuwonus pelamis) liver with potassium phosphate buffer solution. This enzyme was purified by ammonium sulfate fractionation, sepharose CL-6B, QAE-Toyopearl 550C, DEAE-Toyopearl 650M, Bio-gel HT, and Toyopearl HW-55F chromatography. The molecular weight of the enzyme was estimated to be about 110,000 by gel filtration on Sepharose CL-6B. The enzyme was inhibited by Co2+, Cu2+ and Zn2+ ions, but activated by K+, Li+, Na+, Ba2+, and Mn2+ ions.