菠萝蛋白酶催化合成寡聚L-酪氨酸

以菠萝蛋白酶为催化剂从L-酪氨酸甲酯聚合得到寡聚L-酪氨酸(O-L-Try)。 以0.8 U/mL蛋白酶在体积分数为7.5%的二甲亚砜(DMSO)缓冲液(pH=7.5,0.2 mol/L)中催化0.23 g/mL L-酪氨酸甲酯在50 ℃下聚合反应5 h后,O-L-Try产率达到65%。 通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)、氢核磁共振波谱仪(¹H NMR)、拉曼光谱、傅里叶变换红外光谱仪(FTIR)等技术手段表征了O-L-Try结构和性能特征。 结果表明,MALDI-TOF-MS测定的O-L-Try的聚合度主要为10。 ¹H NMR谱图分析得到的O-L-Try的平均聚合度为8。 拉曼光谱显示,O-L-Try的肽键特征峰位于1623 cm^-1(酰胺Ⅰ带)、1447 cm^-1(酰胺Ⅱ带)、1270 cm^-1(酰胺Ⅲ带)和648 cm^-1(酰胺Ⅳ带)。

Synthesis of Oligo-L-Tyrosine via Bromelain

Herein,oligo-L-tyrosine(O-L-Try)was synthesized from L-tyrosine methyl ester with bromelain as the catalyst.The maximal value of O-L-Try yield reached 65% under the optimum reaction conditions of 0.8 U/mL of bromelain,volume fraction 7.5% of dimethyl sulfoxide(DMSO)in phosphate solution(pH=7.5,0.2 mol/L)and 0.23 g/mL of L-tyrosine methyl ester at 50℃ for five hours.The structure of O-L-Try was characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS),hydrogen nuclear magnetic resonance spectroscopy(1H NMR),Raman spectroscopy and Fourier transform infrared spectrometry(FTIR).The polymerization degree of O-L-Try is mainly 10 as measured by MALDI-TOF-MS.The average degree of polymerization of O-L-Try is 8 as determined by 1H NMR analysis.Raman spectroscopy shows that O-L-Try has the characteristic peaks at 1623 cm^-1(amide Ⅰ band),1447 cm^-1(amide Ⅱ band),1270 cm^-1(amide Ⅲ band)and 648 cm^-1(amide Ⅳ band).