Cloning, expression and characterization of alcohol dehydrogenases in the silkworm Bombyx mori

Computational identification of potential bioactive compounds from Triphala against alcoholic liver injury by targeting alcohol dehydrogenase

Alcoholic liver injury resulting from excessive alcohol consumption is a significant social concern. Alcohol dehydrogenase (ADH) plays a critical role in the conversion of alcohol to acetaldehyde, leading to tissue damage. The management of alcoholic liver injury encompasses nutritional support and, in severe cases liver transplantation, but potential adverse effects exist, and effective medications are currently unavailable. Natural products with their potential benefits and historical use in traditional medicine emerge as promising alternatives. Triphala, a traditional polyherbal formula demonstrates beneficial effects in addressing diverse health concerns, with a notable impact on treating alcoholic liver damage through enhanced liver metabolism. The present study aims to identify potential active phytocompounds in Triphala targeting ADH to prevent alcoholic liver injury. Screening 119 phytocompounds from the Triphala formulation revealed 62 of them showing binding affinity to the active site of the ADH1B protein. Promising lipid-like molecule from Terminalia bellirica, (4aS, 6aR, 6aR, 6bR, 7R, 8aR, 9R, 10R, 11R, 12aR, 14bS)-7, 10, 11-trihydroxy-9-(hydroxymethyl)-2, 2, 6a, 6b, 9, 12a-hexamethyl-1, 3, 4, 5, 6, 6a, 7, 8, 8a, 10, 11, 12, 13, 14b-tetradecahydropicene-4a-carboxylic acid showed high binding efficiency to a competitive ADH inhibitor, 4-Methylpyrazole. Pharmacokinetic analysis further confirmed the drug-likeness and non-hepatotoxicity of the top-ranked compound. Molecular dynamics simulation and MM-PBSA studies revealed the stability of the docked complexes with minimal fluctuation and consistency of the hydrogen bonds throughout the simulation. Together, computational investigations suggest that (4aS, 6aR, 6aR, 6bR, 7R, 8aR, 9R, 10R, 11R, 12aR, 14bS)-7, 10, 11-trihydroxy-9-(hydroxymethyl)-2, 2, 6a, 6b, 9, 12a-hexamethyl-1, 3, 4, 5, 6, 6a, 7, 8, 8a, 10, 11, 12, 13, 14b-tetradecahydropicene-4a-carboxylic acid from the Triphala formulation holds promise as an ADH inhibitor, suggesting an alternative therapy for alcoholic liver injury.

Molecular characterization and enzyme inhibition studies of NADP+- farnesol dehydrogenase from diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

Juvenile hormone III (JH III) plays an important role in insect reproduction, development, and behavior. The second branch of JH III production includes oxidation of farnesol to farnesal by farnesol dehydrogenase. This study reported the identification and characterization of Plutella xylostella farnesol dehydrogenase (PxFoLDH). Our results showed that PxFoLDH belongs to the short-chain dehydrogenase/reductase superfamily, consisting of a single domain with a structurally conserved Rossman fold, an NAD(P) (H)-binding region and a structurally diverse C-terminal region. The purified enzyme displayed maximum activity at 55$\ $°C with pH 9.5 and was stable in the temperature below 70$\ ^\circ $C. PxFoLDH was determined to be a monomer with a relative molecular weight of 27 kDa and highly specific for trans, trans-farnesol, and NADP+. Among analog inhibitors tested, farnesyl acetate was the most effective inhibitor with the lowest Ki value of 0.02 µm. Our findings showed this purified enzyme may represent as NADP+-farnesol dehydrogenase.

Purification and enzymatic characterization of alcohol dehydrogenase from Arabidopsis thaliana

Alcohol dehydrogenases (ADH) catalyze the interconversion between alcohols and aldehydes with the reduction of nicotinamide adenine dinucleotide (NAD(+)) to NADH. In this study, for the first time we report an over-expression and purification strategy for the Arabidosis thaliana ADH (AtADH), and characterize its enzymatic properties. AtADH was expressed in an Escherichia coli system, the polyhistidine-tag was removed after the recombinant AtADH protein was purified by metal chelating affinity chromatography. Activity assays demonstrated that AtADH has distinct enzymatic properties when compared with many well-known ADHs. It held peak activity at pH 10.5 and showed broad substrate selectivity for primary and secondary alcohols. The kinetic Km parameters for both ethanol and coenzyme were in the order of mM. This relative low affinity may reflect the need of the plant to maintain a supply of NAD(+) in nature. Different from yeast ADH, AtADH showed almost the same activity for short straight chain alcohols and reduced activity for secondary alcohols. This broad spectrum in alcohol selection and the observed higher catalytic activity (high Vmax (EtOH)) may result from the requirement of the single enzyme to accommodate many substrates.

Molecular cloning and expression of the Streptomyces coniferyl alcohol dehydrogenase gene in Escherichia coli

Coniferyl alcohol dehydrogenase (CADH) is a key enzyme in catabolism of lignin-related aromatic compounds in bacteria. In Streptomyces sp. NL15-2K, CADH is a tetramer of identical subunits with an individual molecular mass of 39 kDa. This work describes the cloning and sequencing of the CADH gene from Streptomyces sp. NL15-2K, optimization of a protocol for high-level active CADH expression, and purification of recombinant CADH. A BLAST search and motif analyses of the predicted CADH amino acid sequence indicated the enzyme belongs to the medium-chain zinc-dependent alcohol dehydrogenase group. Cell density at heat-shock treatment, temperatures for heat shock and culture, duration of heat shock, concentration of isopropyl-β-d-thiogalactopyranoside (IPTG) as an inducer, and culture time after induction were adjusted for optimal CADH expression. Expression of active CADH under optimized conditions was approximately 4-fold higher than in the absence of heat shock. CADH purified from recombinant Escherichia coli was in the tetrameric form, as was natural CADH from NL15-2K.