https://link-springer-com-443.webvpn.jmu.edu.cn/content/pdf/10.1007%2F978-3-319-39782-5_43-1.pdf

Bacterial metabolism of steroids

Chicken gallbladder has long been considered to be worthless and discarded as waste. The main composition of chicken bile is taurochenodeoxycholic acid (TCDCA), which is the isomeride of tauroursodeoxycholic acid (TUDCA). TUDCA has been effectively used for treatment of many diseases. In this paper, 7α- and 7β-hydroxysteroid dehydrogenases (HSDH) were co-immobilised on modified chitosan microspheres, and used as recyclable biocatalyst for the catalysis of chicken bile. The catalytic reaction reached equilibrium within 4 h compared with 1 h using TCDCA as substrate. After four continuous batch reactions, the conversion of TCDCA was lower than 40% and TUDCA yield was about 15% for the catalysis of chicken bile. TUDCA yield was approximately 62% after equilibrium and the content of TUDCA in reaction product was as high as 33.16%. Furthermore, the experiments showed that activity of enzymes were significantly inhibited by bilirubin, Cu2+ and Ca2+ in complex substrate. The research described not only widens the utilization of chicken bile, but also provides a clean way for the preparation of TUDCA.

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Co-immobilised 7α- and 7β-HSDH as recyclable biocatalyst: high-performance production of TUDCA from waste chicken bile

Bile acids are surface-active steroid compounds with a C5 carboxylic side chain at the steroid nucleus. They are produced by vertebrates, mainly functioning as emulsifiers for lipophilic nutrients, as signaling compounds, and as an antimicrobial barrier in the duodenum. Upon excretion into soil and water, bile acids serve as carbon- and energy-rich growth substrates for diverse heterotrophic bacteria. Metabolic pathways for the degradation of bile acids are predominantly studied in individual strains of the genera Pseudomonas, Comamonas, Sphingobium, Azoarcus, and Rhodococcus. Bile acid degradation is initiated by oxidative reactions of the steroid skeleton at ring A and degradation of the carboxylic side chain before the steroid nucleus is broken down into central metabolic intermediates for biomass and energy production. This review summarizes the current biochemical and genetic knowledge on aerobic and anaerobic degradation of bile acids by soil and water bacteria. In addition, ecological and applied aspects are addressed, including resistance mechanisms against the toxic effects of bile acids.

https://www.mdpi.com/2076-2607/9/8/1759/pdf

Degradation of Bile Acids by Soil and Water Bacteria.

A novel NAD(H)-dependent 3alpha-HSDH with enhanced activity by magnesium or manganese ions.

The invention discloses an expression vector for enhancing gene expression of 3 beta-HSD, a construction method and an application thereof. The expression vector comprises a basic sequence, a resistance gene sequence, a multiple cloning site sequence, a starter sequence and a target gene expression segment of a lentiviral vector pLVX-mCMV-ZsGreen-PGK-Puro. The target gene expression segments are forwards inserted between an EcoRI restriction enzyme cutting site and a NotI restriction enzyme cutting site. The expression vector disclosed by the invention can be transfected into human cells, and expresses 3 beta-HSD genes in the human cells in a continuous-stable-efficient manner, also can improve the damage action of a plasticizing agent on tumor cells and is expected to application in anti-tumor drugs.

Expression vector for enhancing gene expression of 3 beta-HSD, construction method and application thereof

Expression, purification and functional characterization of a novel 3α-hydroxysteroid dehydrogenase from Pseudomonas aeruginosa.

The invention discloses a DNA sequence of a polypeptide chain with 3 alpha-HSD (3 alpha-hydroxysteroid dehydrogenase) activity The DNA sequence comprises a complementary chain sequence The DNA sequence is characterized in that an expression product of the DNA sequence has 3 alpha-hydroxysteroid dehydrogenase activity and is a novel Pseudomonas aeruginosa 3 alpha-hydroxysteroid dehydrogenase The DNA sequence comprises the following contents: a pseudomonas aeruginosa 3 alpha-hydroxysteriod dehydrogenase gene sequence obtained by utilizing bioinformatics analysis, a recombinant expression vector which contains the pseudomonas aeruginosa 3 alpha-hydroxysteroid dehydrogenase gene sequence, a genetically engineered bacterium which expresses the 3 alpha-hydroxysteroid dehydrogenase 3-hsdA and an enzyme kinetics parameter of the 3 alpha-hydroxysteroid dehydrogenase

Chen Jianmin

Papers

Expression, purification and functional characterization of a novel 3α-hydroxysteroid dehydrogenase from Pseudomonas aeruginosa.

DNA sequence for expressing 3 alpha-hydroxysteroid dehydrogenase in Pseudomonas aeruginosa