Commelinin and protocyanin are typical metalloanthocyanins. Commelinin consists of 6 molecules each of malonylawobanin (M) and flavocommelin (F), and 2 atoms of magnesium. Electrophoresis data showed the molecular composition of commelinin to be [M_6F_6Mg_2]^<6->; molecular weight being about 9,000. We propose a gross structure of commelinin as shown in Fig. 6. Two copigmented MF units are stacked chirally by hydrophobic interaction between two M molecules to form FMMF unit. Three FMMF units are doubly linked by chelation with two magnesium atoms. Using the gross structure as a reference, X-ray data of Cd-commelinin was analyzed; although the data was not completely solved due to the high molecular weight, six anthocyanidin nuclei could be visualized as shown in Fig. 7. The figure is in good accord with the above gross structure. Protocyanin obtained from blue cornflower, Centaurea cyanus, consists of about 6 molecules each of succinylcyanin and apigenin 4-(6-O-malonylglucoside)-7-glucuronide and one atom each of Fe and Mg. Its gross structure may be very similar to that of commelinin.
