Breakdown of chlorophyll : constituent of nonfluorescing chlorophyll-catabolites from senescent cotyledons of the dicot rape

摘要: The experiments are described in detail, that have led to the elucidation of constitution three colourless metabolites from naturally degreened cotyledons dicot rape (Brassica napus), were characterized earlier be (nonfluorescing) chlorophyll catabolites (NCC's). determination most polar these NCC's B. napus, i.e. Bn-NCC-1 (1), has been communicated preliminary form. Here, further spectroscopic reported, carried out order gain insight into structure 1. In meantime, two other, less nonfluorescing napus (i.e. Bn-NCC-2 (2) and Bn-NCC-3 (3)) could determined by mass spectrometric nuclear magnetic resonance experiments. From studies, Bn-NCC's found linear tetrapyrroles, formally derived pheophorbide a oxidative cleavage porphinoid macrocycle at mesa-position between C(4) C(5) functionalization. These differ each other their nature peripheral substituent only : while 3 ring B C(8) carries free terminal hydroxyl group, latter is esterified malonyl unit 1, glycosylated β-glucopyranosyl group 2. Accordingly, appear intimately related, biosynthetically. Furthermore, basic same as rusty pigment 14 (RP-14 = Hv-NCC-I) artificially primary leaves barley (Hordeum vulgare), with which opening motive for chlorin during catabolism was uncovered laboratories. Indeed, characteristic 4,5-secoporphinoid opened plant chlorophylls, also again structures red green alga Chlorella protothecoides.