Isoquinoline alkaloids are a group of alkaloids which are derived from from tyrosine, some of which have medical applications (PMID:23666088). Typically, the isoquinoline alkaloid biosynthesis pathway begins with L-tyrosine (PMID:23666088). In Arabidopsis thaliana, there are some known reactions of this pathway. With catalyzation by either tyrosine aminotransferase or aspartate aminotransferase, L-tyrosine is reacted with oxoglutaric acid to produce hydroxyphenylpyruvic acid and L-glutamic acid. Alternatively, L-tyrosine may undergo decarboxylation to become tyramine with catalyzation by tyrosine decarboxylase. The hydroxylated form of L-tyrosine, L-dopa, may also undergo decarboxylation catalyzed by tyrosine decarboxylate, forming dopamine. Dopamine may be then used in other pathways, such as the tyrosine metabolism pathway, or undergo further reaction with catalyzation by amine oxidase to produce 3,4-dihydroxyphenylacetaldehyde.

Isoquinoline Alkaloid Biosynthesis References