A NEW POLYAMINE 4-AMINOBUTYLCADAVERINE - OCCURRENCE AND ITS BIOSYNTHESIS IN ROOT-NODULES OF ADZUKI BEAN PLANT VIGNA-ANGULARIS

Root nodules of adzuki bean plant (Vigna angularis) contained a novel polyamine. The chemical structure of the new polyamine was determined to be NH2(CH2)(5)-NH(CH2)(4)NH2 (4-aminobutylcadaverine) based on gas chromatography-mass spectrometry. The occurrence of 4-aminobutylcadave rine was specific to the root nodules, since the unusual triamine was not detected in other organs of the adzuki bean plant. Bacteroids, iso lated from root nodules, contained both sym-homospermidine and 4-amino butylcadaverine, whereas the plant cytosol fraction contained large qu antities of putrescine and cadaverine. A cell-free extract of bacteroi ds showed the ability to form this triamine from putrescine and cadave rine under the presence of NAD(+) and K+. 1,3-Diaminopropane and NADH were inhibitory for the synthesis of both sym-homospermidine and 4 ami nobutylcadaverine. [1,4-N-15]Putrescine was incorporated not only into sym-homospermidine but also into 4-aminobutylcadaverine by the cell-f ree extract of bacteroids when incubated with excess cadaverine. Analy sis of the frag ment ion peaks in the N-15-enriched 4-aminobutylcadave rine indicated the transfer of a aminobutyl moiety to the amino termin us of cadaverine. These results suggest that, in adzuki bean, 4-aminob utylcadaverine is formed through the action of homospermidine synthase in nodule bacteroids under a cadaverine-rich environment.