Food derived tri-peptides; Leucine-Lysine-Proline (LKP) and Isoleucine-Proline-Proline (IPP) are angiotensin converting enzyme inhibitors and may have potential to alleviate hypertension. The aim of this work was to understand the interactions of IPP and LKP when formulated into a chitosan nanoparticle (NP) to help improve permeation. Our findings indicate different mean inhibitory concentrations (LKP: 0.36 ± 0.01 μM and IPP: 3.1 ± 0.6 μM) and encapsulation efficiencies at different ratios of chitosan: tripolyphosphate (LKP NPs: 65% at 6:1 and IPP NPs: 43% at 4:1). Molecular modelling and circular dichroism showed different stable amino side-chain-specific conformations for each peptide. IPP showed more steric hindrances to intra-chain rotations, resulting in an unordered peptide structure, whereas LKP showed more flexibility associated with a (disordered) β-strand-like conformer. In-vitro release kinetics showed a slower release for LKP NPs in acidic pH compared to IPP NPs. In conclusion, LKP NPs were found to have better binding compatibility with chitosan.

食物衍生的三肽；亮氨酸-赖氨酸-脯氨酸（LKP）和异亮氨酸-脯氨酸-脯氨酸（IPP）是血管紧张素转化酶抑制剂，可能具有减轻高血压的潜力。这项工作的目的是了解配制成壳聚糖纳米颗粒（NP）的IPP和LKP的相互作用，以帮助改善渗透性。我们的发现表明不同的平均抑菌浓度（LKP：0.36±0.01μM和IPP：3.1±0.6μM）和不同的壳聚糖：三聚磷酸盐比例时的包封效率（LKP NPs：6：1时为65％，IPP NPs：4时为43％ ：1）。分子建模和圆二色性显示每种肽具有不同的稳定的氨基侧链特异性构象。IPP对链内旋转显示出更多的空间位阻，从而导致无序的肽结构，与IPP NPs相比，在酸性pH下LKP NPs的体外释放动力学显示较慢。总之，发现LKP NP与壳聚糖具有更好的结合相容性。