To investigate the effects of genistein (Gen) on the biosynthesis of N-glycolylneuraminic acid (Neu5Gc) in rats, 80 4-week-old male SD rats were randomly equally into the control and genistein groups. The rats of control and genistein groups were fed 5% ethanol and 300 mg/(kg·d) genistein respectively by gavage. The contents of Neu5Gc in hind leg muscle, kidney and liver tissues of rats were measured by using high performance liquid chromatography coupled with fluorescence detector (HPLC/FLD), and the mechanism of inhibition of Neu5Gc synthesis was investigated by using the molecular docking of Gen and sialyltransferase. On the 15th day, the content of Neu5Gc in hind leg muscle and liver tissues decreased 13.77% and 15.45%, respectively, and there was no significant change in the content of Neu5Gc in kidney tissues. On the 30th day, the content of Neu5Gc in liver tissues decreased 13.35%, however, there was no significant change in the content of Neu5Gc in kidney tissues and Neu5Gc was not detected in hind leg muscle. The content of Neu5Gc in hind leg muscle, kidney and liver tissues decreased respectively 32.65%, 32.78%, 16.80% and 12.72%, 11.42%, 12.30% while rats fed on the 45th and the 60th days. Genistein has formed the hydrogen bond with sialyltransferase activity site residues His319, Ser151, Gly293, Thr328 and formed a hydrophobic interactions with the residues His302, His301, Trp300, Ser271, Phe292, Thr328, Ser325 and Ile274. The results of molecular docking indicated that the weak intermolecular interaction was the main cause of genistein inhibiting sialyltransferase activity. The research results provided an experimental basis for the subsequent reduction of Neu5Gc in red meat before slaughter.
本研究旨在研究染料木黄酮 (Genistein，Gen) 对大鼠体内N-羟乙酰神经氨酸 (N-glycolylneuraminic acid，Neu5Gc) 生物合成的影响。选取80 只4 周龄SD 雄性大鼠，随机平均分为对照组和Gen 组，分别灌胃5%的乙醇溶液和300 mg/(kg·d) 的Gen 溶液。利用荧光高效液相色谱 (HPLC-FLD) 检测大鼠后腿肌肉、肾脏、肝脏组织中Neu5Gc 的含量，并采用Gen 与唾液酸转移酶 (Sialyltransferase，ST) 分子对接，初步探讨了其抑制Neu5Gc 合成的机理。结果表明：灌胃15 d 时，后腿肌肉和肝脏组织中的Neu5Gc 的含量分别降低了13.77%和15.45%，而肾脏组织中Neu5Gc 的含量变化差异不显著；30 d 时，在肌肉组织中未检出Neu5Gc，在肝脏组织中的Neu5Gc 的含量降低了13.35%，肾脏组织中Neu5Gc 的含量没有显著的变化；45 d 时，在后腿肌肉、肾脏组织和肝脏组织中的Neu5Gc 含量分别降低了32.65%、16.80%和32.78%；60 d 时，在后腿肌肉、肾脏组织和肝脏组织中Neu5Gc 含量降低了12.72%、12.30%和11.42%。Gen 与ST 活性位点残基His319、Ser151、Gly293、Thr328 形成氢键，且与残基His302、His301、Trp300、Ser271、Phe292、Thr328、Ser325、Ile274 形成疏水作用。因此分子间弱相互作用是导致Gen 抑制ST 活性的主要原因。该研究结果为后续开展宰前降低红肉中Neu5Gc 的方法提供了基础实验方法支撑。.
Keywords: N-glycolylneuraminic acid; genistein; mechanism; molecular docking; sialyltransferase.