Chinese Journal of Applied Chemistry ›› 2020, Vol. 37 ›› Issue (2): 175-181.DOI: 10.11944/j.issn.1000-0518.2020.02.190224

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Synthesis of Oligo-L-Tyrosine via Bromelain

JIANG Xiaoxiao,ZHU Jinwen,LIAO Xiaofeng,YIN Weiwei,GAO Peng,YANG Changlin,WANG Feng()   

  1. Key Laboratory of Synthetic and Biological Colloids,Ministry of Education,School of Chemical and Material Engineering,Jiangnan University,Wuxi,Jiangsu 214122,China
  • Received:2019-08-21 Accepted:2019-11-04 Published:2020-02-01 Online:2020-02-06
  • Contact: WANG Feng
  • Supported by:
    Supported by the National Scholarship for Studying Abroad(No.201406795023), the Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.SJCX18-0618), and the National Undergraduate Innovation and Entrepreneurship Training Program(No.201910295049)

Abstract:

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).

Key words: bromelain catalysis, oligo-L-tyrosine, structure characterization