ANTICHOLINESTERASE ACTIVITY OF THE FLUORESCENT ZOANTHID PIGMENT, PARAZOANTHOXANTHIN-A

A synthetic linear tetrazacyclopent(t)azulene compound, parazoanthoxan thin A (m.w. 214.2), strongly fluorescent pigment occurring in zoanthi ds, was characterized and assayed for anticholinesterase activity. The pigment, emitting fluorescence at lambda(em) 420 nm, was found to be a pure competitive inhibitor of cholinesterases. At pH 8.0, a K-i valu e of 19 and 26 mu M was determined with insect recombinant, and electr ic eel acetylcholinesterase. Horse serum butyrylcholinesterase was les s sensitive with a K-i of 70 mu M. (C) 1998 Elsevier Science Ltd. All rights reserved.