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Acidic non-protein amino acids and peptides in five species belonging to the family Liliaceae-Smilaxchina, Lilium maximowiczii,Tulipa gesneriana, Alliumcepa and A. sativum-were surveyed. Two newaminoacids-4-hydroxymethyl-and 4-ethyl-4-hydroxyglutamic acid-were isolated from bulbs of T. gesneriana. The first unequivocal identification of 4-ethylglutamic acid was performed from the same plant tissue. A new dipeptide-/S-(2-carboxy-«-propyl)cysteinyl glycine-was isolated from A. cepa. Besides the compounds described above, 4-methylene-, 4methyl-and 4-hydroxy-4-methylglutamic acid were isolated from S. china, L. maximowiczii, and T. gesneriana, but 4-ethylideneglutamic acid was isolated only from T. gesneriana. 4-Methyleneglutamic acid showed no appreciable biological activity, although this amino acid has an a,/?-unsaturated carboxyl group and reacts easily with cysteine in vitro. The most abundant free amino acid in the plant tissues examined in this study is arginine; nevertheless, acidic N*acylarginine derivatives which have been found in S. china and L. maximowiczii and published elsewhere could not be detected in bulbs of T. gesneriana, A. cepa, and A. sativum. Many kinds of sulfur-containing nonprotein amino acids and y-glutamyl peptides have been isolated from AIlium species such as A. cepa (onion), A. sativum (garlic), and A. schoenoprasum (chives) of the family Liliaceae.1* The plants belonging to Tulipa of the same family are famous for containing a variety of 4-substituted glutamic acid derivatives.2~4) Wehave isolated four acidic cysteine derivatives and several acidic peptides from Asparagus officinalis of the same family.5) This report deals with non-protein amino acids and small peptides in tubers of Smilax china (sarutori-ibara), bulbs of Lilium maximowiczii, Tulipa gesneriana, A. cepa, and A. sativum including the isolation of two new amino acids and one peptide, that is, 4-hydroxymethylglutamic acid and 4-ethyl-4-hydroxyglutamic acid from T. gesneriana and 5-(2-carboxy-w

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