the configurational purity of tritium at c-2 of dopamine and c-1 of the dopamine precursor 3-methoxy-4-hydroxyphenethylamine has been confirmed employing dopamine-beta-hydroxylase ( specific for the pro-r hydrogen at c-2 ) and pea seedling amine oxidase ( specific for the pro-s hydrogen at c-1 ) .
C0041119
tritium
C0020275
hydrogen