Occurrence of putreanine in human brain 1

PUTREANINE, a new basic amino acid identified as N-(4-aminobutyl)-3-aminopropionic acid, was recently isolated from bovine brain by KAKIMOTO, NAKAJIMA, KUMON, MATSUOKA, IMAOKA, SANO and KANAZAWA (1969). These workers found putreanine in the brains of several other species of lower mammals and birds, and suggested a biosynthetic route from spermidine. We have now identified as putreanine one of the minor unknown ninhydrin-positive compounds which we had observed in both autopsy and biopsy specimens of human brain (PERRY, BERRY, HANSEN, DIAMOND and MOK 1971a; PERRY, HANSEN, BERRY, MOK and LESK, 19716). Human cerebellar grey matter obtained at autopsy was homogenized and deproteinized in 0.4 M perchloric acid as previously described (PERRY et al., 1971u), and an amount of extract corresponding to 1.1 g wet wt of brain was applied to the ion exchange column of a Technicon amino acid analyser. The column (130 cm) was operated with lithium citrate buffers and a temperature change at 6.5 h from 35" to 70°C (PERRY, STEDMAN and HANSEN, 1968). The entire column effluent was collected for a zone of the chromatogram previously shown to contain a minor ninhydrin-positive peak that was eluted from the column 130 min after histidine and 65 min before arginine. The fraction of column effluent obtained from this preparative chromatogam was then desalted on a column of Dowex 50 x 2 (H+), using a modification of the technique of KAKIMOTO and ARMSTRONG (1962). The compound thus isolated from human cerebellum exhibited the same behaviour as authentic putreanine (Calbiochem, Los Angeles, Calif.) on paper chromatography in two solvent systems, on high voltage paper electrophoresis, and on the automatic amino acid analyser in two different systems. Details are shown in Table 1.