What Is Amineptine?

Aminopeptidases (referred to as APs, EC 3.4.11) are a class of exoproteases that can selectively remove amino acid residues from the N-terminus of proteins and polypeptides to generate free amino acids. Proteases can be divided into two major categories according to the site of action: Endopeptidases and Exopeptidases, of which proteases can be divided into aminopeptidases and carboxypeptidases (Carboxypeptidases).

There are many types of aminopeptidases. Classification of aminopeptidases according to different characteristics is of great help to people's understanding and understanding of aminopeptidases. There are many ways to classify aminopeptidases, such as substrate specificity, location in cells, catalytic characteristics, and optimal pH. The three main classification methods are described below. ^[1]

As a protease, aminopeptidase is widely present in organisms of different species, including mammals, plants, microorganisms, and so on. In animals, a Japanese scholar Akihiro okitani isolated for the first time a proteolytic enzyme with aminopeptidase activity from rabbit skeletal muscle and named it "BANA hydrolase H". Prior to this, Chinese scholar Mei Chuansheng and others reported for the first time a plant-derived aminopeptidase and studied the changes of the enzyme during the senescence of rice leaves. With the in-depth study of aminopeptidase, more and more animal and plant-derived aminopeptidases have been reported.

Due to the complex composition of animals and plants and the low aminopeptidase content, the cost of extraction is high. With the rapid development of the enzyme preparation industry, in order to meet the market demand, the production of enzymes by microbial fermentation has become the mainstream trend and research hotspot today. In 1935, Johnson et al. First discovered aminopeptidase in microorganisms when analyzing enzymes produced by Aspergillus parasiticus. So far, there are many types of reported aminopeptidase-producing microorganisms, mainly divided into two categories: one is eukaryotic microorganisms, including Mucor, Penicillium, Aspergillus, Yeast, etc .; the other is prokaryotic Microorganisms, including Pseudomonas, Lactobacillus, Bacillus, Actinomycetes, etc. ^[1]

Aminopeptidases are widely distributed in nature, and there are significant differences in the expression levels and substrate specificities of aminopeptidases from different sources. Reports of aminopeptidases from animal tissues and plants have been common, but the steps to extract aminopeptidase from plants and animals are complicated and costly. Therefore, the extraction of related aminopeptidases from animals and plants is generally mainly used for enzymatic properties. Characterization and diagnosis of related diseases. Compared with enzymes produced by animals and plants, microorganisms have higher enzyme production, simpler extraction steps, and lower production costs. At present, aminopeptidase products on the market are basically produced by microbial fermentation.

Although there are many types of aminopeptidase-producing microorganisms, most strains are not suitable for large-scale production of aminopeptidase due to low enzyme-producing ability or potential safety hazards. Currently reported wild species that can be used in the industrial production of aminopeptidase are Aspergillus, Bacillus, and Lactobacillus. In 2003, Basten et al. Isolated and purified a new type of phenylalanine aminopeptidase from Aspergillus niger, which can effectively hydrolyze amino acid residues with an aryl side chain at the amino terminus, among which the ability to hydrolyze phenylalanine residues is the strongest. . In 2004, Murai et al. Screened a strain of Aneurinibacillus thermoaerophilus that can produce proline aminopeptidase from hot spring soil. The aminopeptidase produced by this bacteria can synergize with other endoproteases to effectively degrade proline-rich collagen protein It has certain application potential in protein processing and hydrolysate debittering. Although aminopeptidase products have been sold internationally, there are relatively few reports on the production of aminopeptidase by microbial fermentation. Aspergillus oryzae LL1 large tank fermentation research conducted by Taiwan scholar Lin SJ et al. Showed that the levels of aminopeptidase produced by fermentation in 5 L, 20 L, 250 L, 2000 L fermentors can reach 0.22, 0.16, 0.19, 0.12 LAP · mL-1. Data on commercial enzymes show that the commercial aminopeptidase activity produced by Novozymes and Amano is 1200 LAP · g-1 and 500 LAP · g-1, respectively. Gu Haixian, Zhao Guang'ao, etc. from Jiangnan University selected A. oryzae with high yield of aminopeptidase by N + implantation mutagenesis, and optimized the fermentation conditions to increase the enzyme production level by 77.5%. Junichiro et al. Achieved secretory expression of the aminopeptidase derived from Bacillus licheniformis in a Bacillus subtilis expression system, and the yield reached 9U · mL-1 ^[1] .