利巴韦林抗酪氨酸酶活性及其在贡梨中的保鲜应用

Anti-tyrosinase activity of ribavirin and its application in Gong pear preservation

酪氨酸酶是果蔬褐变和黑色素生物合成过程中的关键酶,酪氨酸酶抑制剂在果蔬保鲜和医药领域具有重要意义。该文首次研究了利巴韦林的抗酪氨酸酶活性、机制及其对贡梨鲜切梨块和梨汁的保鲜效果。酶动力学实验的结果表明,利巴韦林是高效、可逆、竞争型的酪氨酸酶抑制剂,其IC_(50)为(0.3±0.05)mmol/L。荧光淬灭和非辐射能量转移实验的结果表明,利巴韦林可静态淬灭酪氨酸酶的内源荧光,且通过1个结合位点与酪氨酸酶形成“利巴韦林-酶”复合物并导致酶的构象发生改变,这一过程伴随着非辐射能量转移。分子对接的结果表明,利巴韦林可以嵌入到酪氨酸酶的活性口袋并与其B链上的6个氨基酸残基(Lys379、Gln356、Gln307、Asp312、Val313、Asn310)形成氢键。贡梨保鲜实验表明,利巴韦林可以有效减少鲜切梨块的失重率和降低梨汁的褐变度。该研究结果为开发新型的果蔬保鲜剂提供了理论依据和实践基础。

Tyrosinase is a key enzyme in browning and melanin biosynthesis of fruit and vegetable,and tyrosinase inhibitors are of great significance in the field of fruit and vegetable preservation,skin whitening and medicine.In this study,ribavirin was first evaluated for its anti-tyrosinase activity and application in the preservation of Gong pear.The results of enzyme kinetics experiments indicated that ribavirin was an efficient[IC_(50)(0.3±0.05)mmol/L],reversible,and competitive type inhibitor of tyrosinase.Nonradiative energy transfer analysis and fluorescence quenching assays demonstrated that ribavirin formed ribavirin-enzyme complex with tyrosinase through one binding site,and accompanied by the change of enzyme conformation and nonradiative energy transfer.The results of molecular docking showed that ribavirin could enter the active center of tyrosinase and form hydrogen bonds with its six amino acid residues(Lys379,Gln356,Gln307,Asp312,Val313,Asn310)on the B chain.The experiment of Gong pears preservation showed that ribavirin could effectively reduce the weight-loss rate of fresh-cut pears and the browning degree of pear juice.The results provided theoretical and practical basis for the development of novel fruit and vegetable preservatives.