尿毒症毒素多肽二级结构的测定和预测

尿毒症患者由于肾脏损伤，使某些代谢物质积蓄在体内而引起中毒，最终导致死亡，由于其分离纯化过程复杂，至今人们对尿毒症中分子积累物的认识仍很有限。目前，已确定的中分子毒物以蛋白质和多肽为主，在前期的工作中，我们从尿毒症患者血清中分离出分子量为1007的中分子物质，实验证明该物质可加速肾衰兔的死亡。

Determination and Forecast of Secondary Structure of Uremic Toxic Polypeptide

A uremic toxic compound with molecular weight 1007.94 was determined to be an octapeptide by mass spectrometry.Its amino-acid sequence was given as follos: Val-Val-Arg-Gly-Cys-Thr-Trp-Trp.Spin systems for amino acid residues in the octapeptide were identified through analysis of 2D NMR ¹H-¹H DQF-COSY,TOCSY and ROESY spectra acquired in H₂O and D₂O.Moreover,the complete assignment of proton resonances for the backbone and side chain was achieved.Based on the secondary chemical shift(Δδ) of the residues,the secondary structure of octapeptide was surveyed.Conformational analyses according to Chemical Shift Index(CSI) showed that the secondary structure of the octapeptide was principally α-helix.The CD spectra of the peptide in aqueous solution gave the same result.Additions of linear polymers made the conformations of octapeptide stretch.These experimental results provide a basis for further comprehension of interaction regulation between biomacromolecule and polymer absorbing materials.