Potentiometric alkali titration data for the full tripeptide set composed from the combination of Glutamic acid (Glu, E), Glycine (Gly, G) and Histidine (His, H), measured between pH 3-12

Peptides were purchased from Genosphere, Sigma Aldrich and Bachem companies. All the peptides were chemically synthesised. Aldrich and Bachem supplied the peptides as their Zwitterionic form, Genosphere synthesised the peptides as tri-fluoro acetic salt TFA salts. The peptides were of purity higher than 98% and were used without any further purification.All peptides solutions were prepared at 0.001M concentration in milliQ water, Hydrochloric acid HCl 0.002M in order to have relatively the same initial pH of 2.6 valueThe potentiometric titrations were recorded at 25°C in 10ml conical flask under Nitrogen atmosphere. NaCLO4 sodium perchlorate was used as ino background at 0.1M to maintain relatively a consistent ionic strength during titration. Standardised NaOH 0.1M was the titrant, and it was added as 5µM increment until pH reaches 11.

本研究所用多肽均购自Genosphere、Sigma Aldrich及Bachem三家公司，所有多肽均为化学合成产物。Sigma Aldrich与Bachem所供多肽以两性离子（Zwitterionic）形式存在，而Genosphere合成的多肽则为三氟乙酸（TFA）盐形式。所有多肽纯度均高于98%，无需额外纯化即可直接使用。所有多肽溶液均以0.001M浓度配制于密理博（MilliQ）超纯水与0.002M盐酸的混合溶剂中，以确保所有样品初始pH值均稳定在2.6左右。电位滴定实验均在25℃下于10ml锥形瓶中、氮气保护气氛下进行。实验采用0.1M高氯酸钠（NaClO₄）作为背景电解质，以维持滴定过程中离子强度相对稳定。以经标定的0.1M氢氧化钠（NaOH）溶液作为滴定剂，每次以5μL增量滴加，直至体系pH值达到11。