Enzymatic Preparation and Inhibitory Mechanism of Xanthine Oxidase Inhibitory Peptides from <i>Undaria pinnatifida</i> Proteins(裙带菜蛋白黄嘌呤氧化酶抑制肽的酶法制备及作用机制)
摘要
Foodborne xanthine oxidase (XO) inhibitory peptides can decrease the production of uric acid via inhibiting the activity of XO, in order to relieve hyperuricemia. Current researches focused on screening XO inhibitory peptides, but their activities were still need to be improved, and the inhibitory mechanisms were not yet clear. <i>Undaria pinnatifida</i> proteins were hydrolyzed by different proteases, and XO inhibitory peptides were screened by chromatographic fractionation and peptide segment identification, of which inhibitory mechanisms were investigated. The combination of papain and <i>Aspergillus niger</i> acid protease (AnproA1) was the best formulation to hydrolyze <i>Undaria pinnatifida</i> proteins with high XO inhibitory activity (92.1%). The hydrolysate was then purified to identify five novel XO inhibitory peptides, including YLGY, VYW, VVSW, TVVW and KVFAW, in which VYW (<i>IC</i><sub>50</sub>=4.3mmol/L) and TVVW (<i>IC</i><sub>50</sub>=2.5mmol/L) showed high XO inhibitory activities. The tryptophan residues on VYW and TVVW formed Pi-Pi stacking and Pi-Alkyl interactions with the active center of XO and other sites, showing non-competitive and competitive inhibitor effect, respectively. XO inhibitory peptides from <i>Undaria pinnatifida</i> protein were prepared by the combination of papain and AnproA1, which would be theoretically and practically important to develop anti-hyperuricemic food ingredients.(食源性黄嘌呤氧化酶(xanthine oxidase, XO)抑制肽通过抑制XO的催化活力,可降低尿酸生成,缓解高尿酸血症。目前研究聚焦于XO抑制肽的制备,但XO抑制肽的活性有待提高,且其作用机制尚未明确。采用不同蛋白酶水解裙带菜蛋白,经色谱分离和肽段鉴定,筛选出XO抑制肽,并探究其作用机制。裙带菜蛋白经木瓜蛋白酶与黑曲霉酸性蛋白酶(AnproA1)复配水解后,所得水解物的XO抑制率(92.1%)最高。从该水解物中筛选出5条新型XO抑制肽:YLGY、VYW、VVSW、TVVW、KVFAW,其中VYW(<i>IC</i><sub>50</sub>=4.3mmol/L)和TVVW(<i>IC</i><sub>50</sub>=2.5mmol/L)具有较高的XO抑制活性。VYW和TVVW的色氨酸残基与XO活性中心及以外位点形成了Pi-Pi堆积和Pi-Alkyl相互作用,分别表现出非竞争型和竞争型抑制作用。利用木瓜蛋白酶和AnproA1复配水解裙带菜蛋白制备XO抑制肽,将为降尿酸功能性食品配料的开发奠定理论基础。)