Synthesis and structure of prolinal-containing peptides, and their use as specific inhibitors of prolyl endopeptidases.
作者:MAKOTO NISHIKATA、HIDEYOSHI YOKOSAWA、SHIN-ICHI ISHII
DOI:10.1248/cpb.34.2931
日期:——
Peptide aldehydes are potent inhibitors of serine and cysteine proteases. In the present work, N-benzyloxycarbonyl (Z) dipeptides containing prolinal at the carboxyl terminus were syntheized as inhibitors of prolyl endopeptidases. Since no aldehyde proton was detected by proton nuclear magnetic resonance (1H-NMR) spectrometry, a cyclic structure was proposed for these peptides. Compounds with a Z-L-X-L-prolinal structure were strong inhibitors of prolyl endopeptidases from the ascidian, Halocynthia roretzi, and Flavobacterium meningosepticum. The potency was in the order of Z-L-Val-L-prolinal≃Z-L-Ile-L-prolinal>Z-L-Phe-L-prolinal>Z-L-Ala-L-prolinal with IC50 values of 10-8-10-6 M order for both enzymes. Conversion of the aldehyde into an alcohol or an acid moiety resulted in a considerable decrease in the inhibitory activity. The diastereomers of Z-L-Phe-L-prolinal were much less inhibitory. This result is not compatible with the reported stereospecifity of the Flavobacterium enzyme for its substrated [T. Yoshimoto, R. Walter and D. Tsuru, J. Biol. Chem., 255, 4786 (1980)]. This implies that the open species binds preferentially to the enzyme active site.
肽醛是丝氨酸和半胱氨酸蛋白酶的强效抑制剂。在本研究工作中,合成了含羧基末端脯氨醛的N-苄氧羰基(Z)二肽,作为脯氨酰内肽酶的抑制剂。由于通过质子核磁共振(1H-NMR)光谱法未检测到醛质子,因此为这些肽提出了一个环状结构。具有Z-L-X-L-脯氨醛结构的化合物是海鞘Halocynthia roretzi和黄杆菌Flavobacterium meningosepticum的脯氨酰内肽酶的强效抑制剂。其效力顺序为Z-L-Val-L-脯氨醛≈Z-L-Ile-L-脯氨醛>Z-L-Phe-L-脯氨醛>Z-L-Ala-L-脯氨醛,IC50值为10-8-10-6 M,对两种酶均有效。将醛转化为醇或酸部分会导致抑制活性显著降低。Z-L-Phe-L-脯氨醛的差向异构体抑制作用较弱。这一结果与黄杆菌酶对其底物的报道立体特异性不一致。这表明开放型物种优先结合到酶活性位点。