Production and characterization of a novel aminopeptidase A from <i>Lactococcus lactis</i>.

Xin Tian; Jinzhou Liu; Zhonghui HE; Linfang Chen; Mengyuan Liu

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Production and characterization of a novel aminopeptidase A from Lactococcus lactis.

Author: Xin TIAN ¹ ; Jinzhou LIU ² ; Zhonghui HE ¹ ; Linfang CHEN ¹ ; Mengyuan LIU ¹
Author Information

1. State Key Laboratory of Biocatalysis and Enzymatic Engineering, School of Life Sciences, Hubei University, Wuhan 430062, Hubei, China.
2. School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan 430065, Hubei, China.
Publication Type:Journal Article
Keywords: Lactococcus lactis subspecies lactis; aminopeptidase A; food industry; meet processing
MeSH: Glutamyl Aminopeptidase; Lactococcus lactis/genetics*; Biological Transport; Culture Media; Glutamic Acid
From: Chinese Journal of Biotechnology 2023;39(8):3494-3507
CountryChina
Language:Chinese
Abstract: Aminopeptidase A (Pep A) is a metal-dependent enzyme that specifically hydrolyze peptides with the N-terminal amino acids glutamic acid (Glu) and aspartic acid (Asp). A possible application of PepA is the hydrolysis of Glu/Asp-rich food proteins such as wheat gluten and casein, increasing the flavor and solubility of food protein. In the present study, the gene encoding a Pep A from Lactococcus lactis ssp. lactis IL1403 was synthesized and introduced into Pichia pastoris GS115 (His4). Lc-Pep A was successfully expressed and secreted to the culture medium, followed by identification and purification to homogeneity. Characteristics study demonstrated that Lc-Pep A could specifically hydrolyze the substrates Glu-pNA and Asp-pNA with similar catalytic activity, and this was further confirmed by the kinetics parameters measured. Additionally, Lc-Pep A showed a broad thermostability and pH stability with an optimum temperature of 60 ℃ and an optimum pH of 8.0. The enzyme activity of Lc-Pep A was activated by metal ions Co²⁺, Mn²⁺, and Zn²⁺ but was strongly inhibited by Ni²⁺and Cu²⁺. The routine proteinase inhibitor had no effect on the activity of Lc-Pep A. However, Lc-Pep A was strongly inhibited by the metallopeptidase inhibitor, EDTA, and disulfide bond-reducing agents. The study may facilitate production and application of Lc-Pep A.