ツノマタより分離した新アミノ酸,S-ヒドロキシメチル-L-ホモシスティンについて

Abstract

Using the displacement chromatography of PARTRIDGE and BRIMLEY, authors succeeded in isolating a new amino acid in crystalline form from Chondrus ocellatus. Properties and structure of the amino acid have been investigated. Results obtained are as follows; 1) Rf values by paper chromatography in phenol, butanol-acetic acid-water and collidine-lutidine were 0.77, 0.15 ?? 0.14 and 0, respectively (Table 1). 2) M. p. 238-239°C, and elementary analysis of the isolate was C, 36.34; H, 6.77; O, 29.51; N, 8.36; and S, 19.02 per cent. Molecular weight determination by cryoscopic method proved 166. The molecular formula based on these values is C5H11O3NS (Table 2). 3) α-Amino-N determination by VAN SLYKE's method gave 8.28 per cent, elucidating that nitrogen of the amino acid is in the form of α-amino N. 4) On the basis of the measurement of optical rotation in water ([α]_??_-73) and in 6N HCl ([α]_??_-31), the isolated amino acid is determined to be L-form. 5) PK values of the amino acid were 2.0, 9.1 and 11.4, respectively (Fig. 1). 6) The presence of OH group was inferred from its positive reaction with diazo and NESSLER's reagents and from its infrared spectrum which showed strong absorption at 1020cm-1 (Fig. 2). The OH group was further proved to be primary by CHANCEL reaction. 7) The amino acid could be reduced mainly to α-amino-n-butyric acid by heating at 60-70°C for 13 hours with RANEY nickel (Figs. 3a and b). 8) The reduction product of the amino acid with 66 per cent HI and red phosphorus at 95°C for 4 hours was found to be identical with that obtained from methionine (Figs. 4 and 5). Ultimately, a new amino acid isolated from Chondrus ocellatus could be established as S-hydroxymethyl-L-homocysteine, which is the only one fitting to all the experimental observa-tions.