PURIFICATION AND PROPERTIES OF AROMATIC L-AMINO-ACID DECARBOXYLASE FROM LIVER OF SKIPJACK TUNA (KATSUWONUS-PELAMIS, TELEOSTEI, SCOMBRIDAE)

Aromatic L-amino acid decarboxylase (AADC; EC 4.1.1.28) was extracted from skipjack (Katsuwonus pelamis) liver with potassium phosphate buff er solution. This enzyme was purified by ammonium sulfate fractionatio n, sepharose CL-6B, QAE-Toyopearl 550C, DEAE-Toyopearl 650M, Bio-gel H T, and Toyopearl HW-55F chromatography. The molecular weight of the en zyme 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 acti vated by K+, Li+, Na+, Ba2+, and Mn2+ ions.