Twenty-two kinds of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) analogs were synthesized and their adjuvant activity on the induction of delayed-type hypersensitivity to ABA-N-acetyl-L-tyrosine was examined. The L-alanine residue of MDP could be replaced with certain other amino acid residues without loss of activity. The structureactivity relationship of these compounds is discussed. With respect to replacement of the L-alanine residue of MDP in connection with adjuvant activity, it was shown that (1) amino acids having a suitable side chain were effective, (2) basic amino acids were unfavorable, (3) aromatic amino acids were unfavorable, and (4) acidic amino acids were effective. The D-isoglutamine residue of MDP was considered to be essential for the adjuvant activity. The adjuvant activity was decreased by esterification with methanol of the D-glutamic acid residue of MDP and related N-acetylmuramyldipeptides, but the adjuvant activity of D-glutamic acid diamide analogs was similar to that of MDP and its analogs.
合成了二十二种
N-乙酰胞壁酰-L-丙
氨酰-D-异谷
氨酰胺(
MDP)的类似物,并检验了它们对诱导对A
BA_
N-乙酰-L-酪氨酸的迟发型过敏反应的佐剂活性。
MDP的
L-丙氨酸残基能为某些其他
氨基酸残基所置换,而活性不变。讨论了这些化合物的结构-活性关系。关于
MDP中
L-丙氨酸残基的置换和佐剂活性,表明; (1)具有合适侧链的
氨基酸是有效的; (2)碱性
氨基酸不是有利的; (3)芳香族的
氨基酸不是有利的; (4)酸性
氨基酸是有效的。认为
MDP的D-异谷
氨酰胺残基对佐剂活性是必要的。与
MDP和有关
N-乙酰胞壁酰二肽的
D-谷氨酸残基的
酯化作用使佐剂活性降低,但
D-谷氨酸二
酰胺类似物的佐剂活性与
MDP及其类似物的佐剂活性相似。