Breakdown of Chlorophyll: A Tetrapyrrolic Chlorophyll Catabolite from Senescent Rape Leaves. Preliminary communication

✍ Scribed by Walter Mühlecker; Bernhard Kräutler; Samuel Ginsburg; Philippe Matile

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: German
• Weight: 348 KB
• Volume: 76
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19930760822

✦ Synopsis

Dedicated to Prof. Duilio Arzgoni on the occasion of his 65th birthday (30.1X.93) The experiments leading to the isolation and to the elucidation of the constitution of Bn-NCC-I, a colourless non-fluorescent chlorophyll catabolite from senescent cotyledons of rape (Brussicn nupus L,), are described. A series of fast-atom-bombardment (FAB) mass and 'Hand "C-NMR spectral experiments are used to determine the constitution of the catabolite Bn-NCC-I. The structural information available indicates Bn-NCC-I to be a l-formyl-19-oxobilane, structurally related to 'RP 14, isolated earlier from artificially aged primary leaves of barley. The major differences between the constitution of the metal-free chlorophyll pheophorbide a and that of Bn-NCC-I concern oxygenolytic opening of the porphinoid macrocycle at C(4)-C( 5), saturation at the other meso positions, hydrolysis of the methyl-ester function, and functionalization by a malonic-acid unit of the side chain at C(8). This work provides for the first time the structural data of a chlorophyll-degradation product from senescent plant leaves formed under normal growth conditions.