Involved in the biosynthesis of the common precursor of all benzylisoquinoline alkaloids such as morphine, sanguinarine, codeine or berberine. Condenses dopamine and phenylacetaldehyde, 3,4-dihydrophenylacetaldehyde or 4-hydroxyphenylacetaldehyde. (4-hydroxyphenyl)acetaldehyde + dopamine = (S)-norcoclaurine + H2O Binds 1 Fe cation per subunit. Inhibited by O-phenanthroline, but not by EDTA. Monomer. NCS1 is a 2-oxoglutarate-independent dioxygenase-like protein that catalyzed the cyclase reaction without oxygen. Belongs to the iron/ascorbate-dependent oxidoreductase family.