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酪蛋白磷酸肽副产物中仍含有丰富的功能性多肽,从中回收具有降压活性的血管紧张素I转化酶抑制肽具有废物利用和环境保护的意义。本文在前期研究富集活性肽工艺的基础上,从粗富集产物中进一步分离纯化出具有降压活性的多肽单体,并对单体的分子量、一级序列及其稳定性进行了研究。研究结果表明,以粗富集产物为原料,仅通过阴离子交换树脂及液相制备两步就可获得活性较高的转化酶抑制肽单体P16和P18。P16分子量742.6,序列为GPFPIIV,属首次发现;P18分子量1385.8,序列为FFVAPFPE VFGK。二者均具有较高的耐酸碱性和热稳定性,经体外模拟胃肠消化过程后,发生不同程度的分解,但P16的活性在分解后反而升高12.8%,P18则降低37.5%。推测活性的升高或降低均与活性中心暴露或破坏有关。
Casein phosphopeptide is still rich in functional peptides in the by-products, from which the angiotensin I-converting enzyme inhibitory peptide with antihypertensive activity has the meaning of waste utilization and environmental protection. Based on the previous studies on the enrichment of active peptides, the peptide monomers with antihypertensive activity were further isolated and purified from the crude enriched products. The molecular weight, primary sequence and stability of the monomers were also studied. The results show that the crude enzyme-rich products as raw materials, only by anion exchange resin and liquid preparation two steps can be obtained more active invertase inhibitor peptide monomers P16 and P18. P16 molecular weight of 742.6, the sequence of GPFPIIV, is the first discovery; P18 molecular weight 1385.8, the sequence FFVAPFPE VFGK. Both of them had higher acid and alkali resistance and thermal stability. After in vitro digestion, the activity of P16 increased by 12.8% and P18 decreased by 37.5%. It is speculated that the increase or decrease of activity is related to the active center exposure or destruction.