血红蛋白β-链片段合成及生物活性

Synthesis and biological activities of β-chain fragments of hemoglobin

为探讨血红蛋白β-链片段的血管紧张素Ⅰ转换酶(angiotensin Ⅰ-converting enzyme,ACE)抑制活性,采用微波固相合成法以Wang树脂或2-氯三苯甲基氯树脂为固相载体,以9-芴甲氧羰基(9-fluorenylmethyl-oxycarbonyl,Fmoc)为N-端氨基酸保护基,以O-苯并三氮唑-N,N,N',N'-四甲脲六氟磷酸酯(O-benzotriazole-N,N,N',N'-tetramethyl-uronium-hexafluorophosphate,HBTU)和1-羟基-苯并三氮唑(N-hydroxybenzotrizole,HOBt)为缩合试剂,合成了17个血红蛋白β-链片段。生物活性研究结果表明:片段Val-Val-Tyr-Pro-Trp-Thr的ACE抑制活性最高,IC50达7.42μmol·L-1,Val-Val-与-Gln-Arg-Phe为Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe的两个活性中心,当N-端含支链的疏水性氨基酸如Val、C-端末三位氨基酸含有Phe、Trp、Arg时活性较强;高浓度条件下表现有一定的体外降血糖活性,但合成片段的体外抑菌活性与抗肿瘤活性不十分明显。

To investigate the angiotensin I-converting enzyme （ACE） inhibitory activity of β-chain hemoglobin fragments, 17 fragments were synthesized by microwave-assisted solid-phase synthesis method. Wang resin or Trt（2-Cl） resin, Frnoc and HBTU-HOBt were used as solid carrier, N-terminal amino acid protecting groups and coupling reagents, respectively. The ACE inhibitory, a-glucosidase inhibitory, antibacterial and antitumor activities of the synthesized fragments were assayed. In vitro, Val-Val-Tyr-Pro-Trp-Thr showed high ACE inhibitory activity （IC50 =7.42 μmol·L^-1）. The results indicate that there are two active sites in Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe, one consists of Val-Val-, and the other -Gln-Arg-Phe. Peptides showed high ACE inhibitory activity when the N-terminal was hydrophobic amino acid such as Val and C-terminal tripeptide contained Phe, Trp or Arg. Some of the fragments showed low α-glucosidase inhibitory activity. No antibacterial activity or antitumor activity was detected in vitro. The results indicate that these peptides have a potential antihypertensive effect and possible application in the treatment of hypertension.