N-Methyl tyramine

The dried rinds of the fruits of Citrus unshiu and C. aurantium var. daidai are known as Chin-pi or Toh-hi in Japan, respectively, and the immature fruits of these plants are called Ki-jitsu. These are also used in Kampo medicine, and from them, the phenylethylamine-type alkaloids N-methyl-tyramine and synephrine were isolated [6,7]. 

The toxic prindple is believed to be sympalhomimelic amines, tyramine, N-methyl tyramine, and N-methyl-p-phenylelliylamine, which are monoamine oxidase (MAO) inhibitors. The toxin is presm in the leaves. 

Two distinct enzymes tyramlne-W-methyltransferase, and N methyl-tyramine-JV-methyltransferase were isolated and separated. They differed in their pH optimum and their stability). 

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