Heterologous Expression and Characterization of Tyrosine Decarboxylase from Enterococcus faecalis R612Z1 and Enterococcus faecium R615Z1

文献类型： 外文期刊

第一作者： Liu, Fang

作者： Liu, Fang;Xu, Wenjuan;Wang, Daoying;Zhu, Yongzhi;Geng, Zhiming;Zhang, Muhan;Xu, Weimin;Du, Lihui

作者机构：

期刊名称：JOURNAL OF FOOD PROTECTION （ 影响因子：2.077； 五年影响因子：2.224 ）

ISSN： 0362-028X

年卷期： 2014 年 77 卷 4 期

页码：

收录情况： SCI

摘要： Tyrosine decarboxylase (TDC) is responsible for tyramine production and can catalyze phenylalanine to produce beta-phenylethylamine. Enterococcus strains are a group of bacteria predominantly producing tyramine and beta-phenylethylamine in water-boiled salted duck. In this study, the heterologous expression and characterization of two TDCs from Enterococcus faecalis R612Z1 (612TDC) and Enterococcus faecium R615Z1 (615TDC) were studied. The recombinant putative proteins of 612TDC and 615TDC were heterologously expressed in Escherichia coli. 612TDC is a 620-amino-acid protein with a molecular mass of 70.0 kDa, whereas 615TDC is a 625-amino-acid protein with a molecular mass of 70.3 kDa. Both 612TDC and 615TDC showed an optimum temperature of 25 degrees C for the tyrosine and phenylalanine substrates. However, 612TDC revealed maximal activity at pH 5.5, whereas 615TDC revealed maximal activity at pH 6.0. Kinetic studies showed that 612TDC and 615TDC exhibited higher specificity for tyrosine than for phenylalanine. The catalysis abilities of both 612TDC and 615TDC for phenylalanine were restrained significantly with the increase in NaCl concentration, but this was not the case for tyrosine. This study revealed that the enzyme properties of the purified recombinant 612TDC and 615TDC were similar, although their amino acid sequences had 84% identity.

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