Understanding the molecular mechanisms underlying protein-flavonoid interactions is crucial for the application of protein-flavonoid complexes in food. The purpose of this study was to explore the factors that influence the efficient release of rutin (Rut) and isoquercitrin (Iso) from Lactobacillus acidophilus β-glucosidase (BGL) and the interaction mechanism among rutin, isoquercitrin and β-glucosidase. Spectroscopic analysis, atomic force microscopy and molecular docking studies showed that Rut or Iso quenched the intrinsic fluorescence of β-glucosidase in a static manner through the formation of a flavonoid-β-glucosidase complex. Atomic force microscopy and circular dichroism measurements confirmed that the conformation of β-glucosidase changed slightly. Molecular docking further proved that the interaction force of Rut or Iso with β-glucosidase was hydrogen bonding, hydrophobic interactions and electrostatic interactions, and the binding free energies of the interactions were −180.54 kcal mol⁻¹ and -119.35 kcal mol⁻¹, respectively. Substituted groups on the glycosylation of quercetin glycoside compounds are crucial for their binding to β-glucosidase. This study provides a theoretical basis for the design of natural flavonoid-protein complex functional foods.

了解蛋白质-类黄酮相互作用的分子机制对于蛋白质-类黄酮复合物在食品中的应用至关重要。本研究旨在探讨影响嗜酸乳杆菌芦丁（Rut）和异槲皮苷（Iso）有效释放的因素。β-葡萄糖苷酶（BGL）和芦丁、异槲皮苷和β-葡萄糖苷酶的相互作用机制。光谱分析、原子力显微镜和分子对接研究表明，Rut 或 Iso 通过形成类黄酮-β-葡萄糖苷酶复合物以静态方式猝灭 β-葡萄糖苷酶的固有荧光。原子力显微镜和圆二色性测量证实β-葡萄糖苷酶的构象略有变化。分子对接进一步证明Rut或Iso与β-葡萄糖苷酶的相互作用力为氢键、疏水相互作用和静电相互作用，相互作用的结合自由能分别为-180.54 kcal mol ^-1和-119.35 kcal mol ^-1， 分别。槲皮素糖苷化合物糖基化上的取代基团对于它们与 β-葡萄糖苷酶的结合至关重要。本研究为天然黄酮-蛋白质复合功能食品的设计提供理论依据。