A Convenient Method for the Prepara - tion of iV - / J - Alanyldopamine as a Substrate of

/V-/j-Alanyldopamine (NBAD) has attracted a great deal of interest because of its significance in catecholamine metabolism in insects with which phenoloxidase is concerned.1' Kramer et al. synthesized NBADby coupling the acid component of /V-/?-alanine with the amine component of dopamine in aqueous solution.2' Their method, however, required several chromatographic steps to purify the synthetic compound. We recently found a method to prepare NBADmore conveniently. This report describes a new synthetic method of NBADand the oxidation of NBAD by housefly phenoloxidase using this synthetic compound. Phenoloxidase (EC 1.14.18.1 in part) was prepared by the method of Shimoda et al3) from housefly {Musca domestica vicina) pupae three days after puparium formation and its activity was measured as described previously.4' Boc-BA-ONSuwas synthesized by the method of Smirnov et al.5) NBADwas synthesized as follows: Boc-BAD (1). To a solution ofdopamine hydrochloride (984mg, 5mmol) in dimethylformamide (5ml) Boc-BAONSu (1.43g, 5mmol) and triethylamine (1.28ml,