Enzymatic Reaction Research Articles

A review of the Bovis Calculus’s intervention mechanism and clinical application in ischemic stroke

BackgroundBovis Calculus (BC), also named Niuhuang in Chinese, is utilized as a resuscitation drug in Traditional Chinese Medicine (TCM) for the treatment of neurological disorders. Ischemic stroke (IS) is a significant global public health issue that currently lacks safe and effective therapeutic drugs. Ongoing efforts are focused on identifying effective treatment strategies from Traditional, Complementary, and Integrative Medicine. Noticeably, BC has been used in TCM for thousands of years to prevent or treat IS-related diseases.MethodsThe historical origins of BC in the treatment of IS were investigated through the examination of ancient Chinese medical texts. Furthermore, the chemical components of BC were analyzed, and its mechanisms of action against IS were summarized using literature sourced from databases such as Web of Science, PubMed, and China National Knowledge Infrastructure. Information on Chinese medicine preparations and clinical reports was also integrated to provide an overview of modern applications and safety considerations.ResultsBC mainly includes chemical components such as bile pigments, bile acids, cholesterol, proteins amino acids, and trace elements. Additionally, the efficacy of BC in treating cerebral ischemia/reperfusion injury (CI/RI) is certain, particularly due to the components of bile pigments, bile acids, and amino acids that can interfere with the enzymatic cascade reaction of CI/RI through multiple components, targets, and pathways. The active components of BC exert neuroprotective effects by reducing microcirculation disturbance, excitatory amino acid toxicity, and oxidative stress injury in the acute stage; inhibiting inflammatory injury, apoptosis, and blood-brain barrier (BBB) disruption in the subacute stage; and promoting angiogenesis and neurogenesis in the restoration stage. Furthermore, as a crude drug, BC appears in many Chinese patent medicine (CPM) preparations for the treatment of IS, and clinical and preclinical studies have proved its safety.ConclusionThe use of BC in the treatment of IS has a long history, proven efficacy, and widespread application. Future efforts should focus on elucidating its mechanisms of action and exploring its applications.

Synthesis of Enantioenriched 2‐((Hetera)Cyclo) Alkylchromanols and their Spirocyclic Analogs through Enzymatic Resolution

AbstractAn efficient approach to the multigram synthesis of 2‐((hetera) cyclo) alkylchromanols and their spirocyclic analogs based on enzymatic resolution is described. It is shown that enzymatic acylation could be used for the preparation of enantioenriched title compounds with primary alkyl substituents at the C‐2 position. Meanwhile, enzymatic hydrolysis of the corresponding acetates was optimal for the preparation of the target alcohols when significant steric hindrance is present, e. g., due to the α‐branching. The latter factor was demonstrated to be crucial for the enzymatic reaction rate in both cases. The synthetic utility of the obtained chiral alcohols was demonstrated through Mitsunobu configuration inversion, as well as by preparation of the corresponding primary amines – valuable sp3‐enriched building blocks for medicinal chemistry.

Recommendations and guidance on Cobalamin (Vitamin B12) based on the Delphi method

Introduction: Vitamins are essential micronutrients for the body to function. Cobalamins (Cbls) are watersoluble compounds, acting as cofactors in enzymatic reactions. However, the use of Cbls in the clinical environment is still controversial. Objective: It was to discuss the topic and help guide different professionals, experts were brought together to discuss criteria concerning the diagnosis, indications, and use of cobalamin. Methods: The study was carried out using the Delphi method. Topics were initially created to direct the discussion and initial contributions. In the first meeting with the panelists, questions were formulated. The questions were distributed to all panelists. With the contributions, a text with the answers was created, and a third round to review the contributions and agree with the text was carried out. Results: The main topics related to the use of cobalamin were identified. Conclusion: The main topics related to this topic include risk groups of deficiency of ingestion or absorption by the gastrointestinal tract. The deficiency diagnosis must be made through laboratory tests, and early indication must be made when a significant cobalamin deficiency is identified, to avoid irreversible clinical conditions. A recommended practice is monitoring between 2 and 6 months after starting cobalamin replacement. Evidence Level:6.

Two‐Level Spatially Localized Proximity Labeling for Cross‐Biological‐Hierarchy Measurement and Manipulation

Proximity labeling (PL) has emerged as a powerful technique for the in situ elucidation of biomolecular interaction networks. However, PL methods generally rely on single‐biological‐hierarchy control of spatial localization at the labeling site, which limits their application in multi‐tiered biological systems. Here, we introduced another enzymatic reaction upstream of an enzyme‐based PL reaction and targeted the two enzymes to markers indicating different biological hierarchies, establishing a two‐level spatially localized proximity labeling (P2L) platform for in situ molecular measurement and manipulation. Using the cellular‐ and glycan‐level as the hierarchical models, we demonstrated the ability of P2L to efficiently execute a two‐step logic operation and to discriminate target cells with different levels of glycosylation within mixed cell populations. By mounting clickable handles via P2L, we reprogrammed the robust covalent assembly of cells at designated sites. The combination of P2L with proteomics led to the profiling of the protein microenvironment of specific glycans on target cells, revealing changes in tumor‐cell‐surface interactions under immune pressure from a glycan perspective. P2L provides not only a solution for revealing the heterogeneity of biological systems, but also new insights in the fields of intelligent logic computation, enzyme engineering, tissue engineering, etc.

Two-Level Spatially Localized Proximity Labeling for Cross-Biological-Hierarchy Measurement and Manipulation.

Proximity labeling (PL) has emerged as a powerful technique for the in situ elucidation of biomolecular interaction networks. However, PL methods generally rely on single-biological-hierarchy control of spatial localization at the labeling site, which limits their application in multi-tiered biological systems. Here, we introduced another enzymatic reaction upstream of an enzyme-based PL reaction and targeted the two enzymes to markers indicating different biological hierarchies, establishing a two-level spatially localized proximity labeling (P2L) platform for in situ molecular measurement and manipulation. Using the cellular- and glycan-level as the hierarchical models, we demonstrated the ability of P2L to efficiently execute a two-step logic operation and to discriminate target cells with different levels of glycosylation within mixed cell populations. By mounting clickable handles via P2L, we reprogrammed the robust covalent assembly of cells at designated sites. The combination of P2L with proteomics led to the profiling of the protein microenvironment of specific glycans on target cells, revealing changes in tumor-cell-surface interactions under immune pressure from a glycan perspective. P2L provides not only a solution for revealing the heterogeneity of biological systems, but also new insights in the fields of intelligent logic computation, enzyme engineering, tissue engineering, etc.

A Multifaceted Luminescent Europium(III) Probe for the Discrimination of Nucleoside Phosphates and Detection of Organophosphate Nerve Agents.

The nucleotides play multiple fundamental roles that are essential in biochemical enzymatic reactions and signaling pathways. Many diseases are closely associated with their dysregulation. Therefore, reliable and sensitive optical probes to discriminate various nucleotides are essential in biochemistry, drug discovery, and disease diagnosis. Furthermore, developing reliable, easy-to-use optical sensors for extremely toxic organophosphonates/nerve-agents is critical to counter public health threats. Luminescent lanthanide(III) complexes have emerged as promising optical bioprobes owing to intraconfigurational f → f transitions. Herein, we present strategically designed Eu(III) probes: [Eu(THC)(X)3]Cl (Eu.1) and [Eu(TBC)(X)3]Cl/Br (Eu.2) containing pentadentate terpyridine dicarboxylates: 4'-(3,4,5-trihydroxyphenyl)-[2,2':6',2″-terpyridine]-6,6″-dicarboxylic acid (THC) and 4'-phenyl-[2,2':6',2″-terpyridine]-6,6″-dicarboxylic acid (TBC) and X = solvent. The Eu.1 probe is systematically evaluated for discrimination of various NPs and as a luminescent chemodosimetric probe for diethyl chlorophosphate (DCP) as a G-series nerve agent mimic. The time-delayed luminescence is used for discrimination between various adenine-based NPs under physiological conditions. The Eu.1 probe shows high affinity and selectivity for ADP enabling continuous monitoring of the ADP/ATP ratio in a simulated enzymatic reaction. Additionally, Eu.1 acted as a chemodosimetric probe for DCP. The interaction produces a change in the sensitization pathway, enhancing the Eu(III)-based luminescence with a ppb level of detection of DCP (LOD = 758 ppb). Our innovative approach expands applications of lanthanide luminescence for probing nucleotides and the detection of lethal nerve agents.

Rational design of redox active metal organic frameworks for mediated electron transfer of enzymes.

The efficient immobilization of redox mediators remains a major challenge in the design of mediated enzyme electrode platforms. In addition to stability, the ability of the redox-active material to mediate electron transfer from the active-site buried enzymes, such as flavin adenine dinucleotide-dependent glucose dehydrogenase (FADGDH) and lactate oxidase (LOx), is also crucial. Conventional immobilization techniques can be synthetically challenging, and immobilized mediators often exhibit limited durability, particularly in continuous operation. Here, we design a novel redox-active cobalt-based metal-organic framework (raMOF) obtained via the partial ligand substitution of 2-methylimidazole (MeIm) with a 1,2-naphthoquinone-4-sulfonate (NQSO) redox probe, as a promising platform for high-performance enzyme electrodes. This nanostructured raMOF, combined with multi-walled carbon nanotubes (CNTs), provided a high current density of up to 2.06 mA cm-2 during enzymatic reactions and maintained remarkable operational stability, retaining 100% of its current over 54 hours. This stability far exceeded that of adsorbed NQSO on CNTs, which experienced a complete loss of the initial current, highlighting the significant advantage of the raMOF-based platform for high-performance enzyme electrodes.

Development of a Semiquantitative Barcode Readout Approach for Paper-Based Analytical Devices (PADs) for Enzymatic H2O2 and Glucose Detection.

The integration of barcode technology with smartphones on paper-based analytical devices (PADs) presents a promising approach to bridging manual detection with digital interpretation and data storage. However, previous studies of 1D barcode approaches have been limited to providing only a "yes/no" response for analyte detection. Herein, a method of using barcode readout for semiquantitative signal detection on PADs has been achieved through the integration of barcode technology with a distance-based measurement concept on PADs. To demonstrate the feasibility of this concept, a PAD fabrication strategy incorporating barcodes was explored, using the enzymatic reaction between horseradish peroxidase (HRP), 3,3'-diaminobenzidine (DAB), and H2O2 as a model system. The enzyme-catalyzed polymerization of DAB to polyDAB in the presence of hydrogen peroxide results in the appearance of color observable by the naked eye inside a paperfluidic channel, with the color-changed length depending on the H2O2 concentration. At the same time, the barcode pattern displayed as a result of this distance-based color evolution overlaid with a paper-based barcode layer can be read using a smartphone application. Parameters affecting the signal readout performance were studied. The developed device can be used to detect H2O2 concentrations in the range of 0.25 to 10 mM within 90 min with 79.6% of barcode signals correctly readable. Additionally, results from different smartphone models showed a consistent reading performance (78.4-79.6%). Finally, the quantification of glucose levels in artificial urine samples was demonstrated. This developed PAD signaling strategy offers end-users more simplicity and can be used as a standalone device or in conjunction with other digital devices.

Fabrication of Compartmentalized Multienzyme Reactor for Colorimetric Biosensing of Glucose and Phenol with High Sensitivity.

Enzymatic cascade reactions are widely utilized in food security, environmental monitoring, and disease diagnostics, whereas their practical application was hindered due to their limited catalytic efficiency and intrinsic fragility to environmental influences. Herein, a compartmentalized dual-enzyme cascade nanoreactor was constructed in metal-organic frameworks (ZIF-8) by a shell-by-shell growth method. ZIF-8 provided a good microenvironment to maintain the activity of enzymes and protected them against harsh conditions. Importantly, experimental results revealed that the encapsulation order and enzyme ratio affected the cascade catalytic activity. When the cascade enzyme ratio was 1:1 and horseradish peroxidase (HRP) was encapsulated in the inner layer with glucose oxidase (GOx) in the outer layer (H@ZIF-8@G@ZIF-8), the nanoreactor facilitated the mass transfer process of substrates and showed the highest cascade catalytic efficiency. The maximum reaction rate (Vmax) of H@ZIF-8@G@ZIF-8 was 294.96 nM s-1, which was 1.6 times greater than G@ZIF-8@H@ZIF-8 (182.84 nM s-1). Therefore, H@ZIF-8@G@ZIF-8 was effectively applied in glucose monitoring and phenol sensing. The glucose biosensor showed a low detection limit of 0.76 μM and a broad linear range of 5-300 μM. The phenol biosensor demonstrated a wide linear range (20-300 μM) with a detection limit of 0.60 μM. In addition, the spiked recovery experiments for glucose and phenol were carried out in serum (recovery: 95.26-100.04%) and tap water (recovery: 97.05-106.50%), respectively. The high accuracy demonstrated potential applications of the cascade system in biosensing and environmental detection.

Penicillin G Acylase: A Multifunctional Catalyst with Broad Implications in Pharmaceutical Science and Industrial Applications

Abstract: Penicillin G Acylase (PGA) has emerged as a critical biocatalyst in pharmaceutical sciences, exceeding its traditional role in penicillin synthesis. Despite its industrial significance, challenges, including substrate specificity, stability under industrial conditions, and efficiency in immobilization, persist. Engineering enhanced enzyme variants and developing advanced immobilization techniques along with process optimization shall be possible solutions to further improve reaction efficiency and scalability. Green chemistry integration can make PGA-based processes more sustainable. Moreover, the use of computational tools, including AI-driven optimization, can guide enzyme design and reaction condition refinement. A review synthesizing these advancements not only consolidates existing knowledge but also identifies opportunities for further innovation, ensuring the enzyme’s continued industrial and scientific relevance. The review discusses the structure and functionality of PGA, highlighting its diverse applications beyond penicillin production. Beyond antibiotic synthesis, PGA's usefulness extends to ester synthesis, resolving racemic mixtures and peptide bond formation, underlining its importance in various bioconversions and synthetic reactions. This adaptability is crucial for green chemistry, promoting sustainable practices in industrial processes. The kinetic parameters of PGA are discussed, providing insights into its operational efficiency. Despite its significant potential, PGA faces limitations in commercial applications, primarily due to stability issues under industrial conditions. Efforts to enhance PGA's stability, including engineering approaches, are explored to improve its industrial applicability. The review concludes by emphasizing PGA's role as a catalyst with vast implications in science and medicine, particularly in an era of rising antibiotic resistance. It underscores the enzyme's interconnected roles in production and therapeutics, its broad spectrum of applications, and the shift from traditional penicillin synthesis to broad-spectrum bioconversions. The scope of PGA engineering is also highlighted, indicating future directions for research and application in the pharmaceutical industry.

Vesicle-Encapsulated Chemosensing Ensembles Allow Monitoring of Transmembrane Uptake Coupled with Enzymatic Reactions.

Compartmentalized models with coupled catalytic networks are considered as "protocells" in the context of research related to the origin of life. To model the kinetics of a simple cellular uptake-metabolism process, we use a compartmentalized protocell system that combines liposome-encapsulated intravesicular reporter pairs with co-encapsulated enzymes to monitor the membrane transport of a substrate (analyte uptake) and its subsequent enzymatic reaction inside the vesicles (metabolism to the product). The intravesicular chemosensing ensembles consist of the macrocycles cucurbit[7]uril or p-sulfonatocalix[4]arene and matching fluorescent dyes to set up suitable reporter pairs. When these macrocycle/dye reporter pairs are co-encapsulated with enzymes (trypsin, protein kinase A, or butyrylcholinesterase), it is possible to monitor first the transport of different substrates (polylysine, protamine, H-LRRWSLG-OH, or butyrylcholine) through added pores (outer membrane proteins F and C), with synthetic carriers (amphiphilic calixarenes), or by direct permeation (only for butyrylcholine). The subsequent enzymatic conversions of the substrates after they have entered the corresponding protocells can be monitored as consecutive reactions. The new type of in vitro assays can be applied to different enzymes and analytes, affording a comprehensive chemosensing system of high chemical complexity.

Vesicle‐Encapsulated Chemosensing Ensembles Allow Monitoring of Transmembrane Uptake Coupled with Enzymatic Reactions

Vesicle‐Encapsulated Chemosensing Ensembles Allow Monitoring of Transmembrane Uptake Coupled with Enzymatic Reactions

Anaerobic sludge digestion enhancement with bioelectrochemical and electrically conductive materials augmentation: a state of the art review.

Excess biological sludge processing and disposal have a significant impact on the energy balance and economics of wastewater treatment operations, and on receiving environments. Anaerobic digestion is probably the most widespread in-plant sludge processing method globally, since it stabilizes and converts biosolids organic matter into biogas, allowing partial recovery of their embedded chemical energy. A considerable number of studies concerning applicable techniques to improve biogas production, both in quantity and quality, include pre-treatment strategies to promote biosolids disintegration aimed at the release and solubilisation of intracellular energy compounds, inorganic/biological amendments aimed at improving process performance, and sludge thermal pre-treatment. As for in-process amendments, iron, micro and macro-nutrients, ashes from waste incineration and nanoparticles addition have been studied for the improvement of enzymatic reactions. Recently, use of electrically conductive materials has been credited with the possibility to accelerate and stabilize the conversion of organic substrates to methane. The possibility of increasing both biogas generation and its relative biomethane content by interfacing anaerobic digestion with bioelectrochemical systems was also postulated. This review addresses the research gap surrounding the integration of anaerobic digestion with novel technologies, particularly bioelectrochemical systems, to enhance biogas production and methane enrichment. While existing studies focus on pre-treatment and in-process amendments, the feasibility, mechanisms, and benefits of such integration remain underexplored. By critically evaluating the current state of the art, this review identifies the potential of bioelectrochemical integration to improve energy recovery and process stability, while highlighting key challenges and research needs for advancing these technologies toward practical implementation.

Identification of ketamine and norketamine in dried bloodstains on crime-scene surfaces

BackgroundToxicological analysis of dried bloodstains (DBS) provides critical information for reconstructing the sequence of events at a crime scene. Drugs have higher stability in DBS relative to liquid blood owing to the arrest of enzymatic reactions in dehydrated samples. However, literature on the identification of ketamine and its metabolites in DBS is limited and is mostly focussed on the analysis of bloodstains collected on paper cards. The present study has analysed the stability of ketamine and norketamine in DBS aged on common crime scene surfaces under various storage temperatures. Coloured linen fabric and glass slide, representing porous and non-porous surfaces, respectively, were stained with a defined volume of drug-fortified whole blood and stored at room temperature (20 °C), in the refrigerator (4 °C), and freezer (− 20 °C) for 1, 7, and 14 days. Analytes were solvent-extracted using a dichloromethane: hexane (1:3 v/v) mixture, followed by gas chromatography-mass spectrometry (GC–MS) analysis with ketamine-d4 as the internal standard.ResultsAt least 4.3 ng/mL and 8.7 ng/mL ketamine and norketamine, respectively, were detected in dried stains prepared from 5 to 50 µL whole blood corresponding to a concentration range of 10–100 ng/mL. The GC–MS method was linear in this range with a coefficient of determination, R2 > 0.99. Recovery of the analytes was comparable (~ 100–120%) between DBS porous and whole blood, whereas it was considerably lower (~ 50%) in DBS non-porous samples due to the incomplete transfer of the stains from the glass into the extraction solvent mixture. Analyte response in DBS showed a strong correlation with that in whole blood at four concentration levels (0.1–5 µg/mL). Mean precision values (% CV) for biological and technical replicates (n = 5) were 15.0 and 6.5, respectively, and within an acceptable range.ConclusionsThe developed method for the analysis of ketamine and norketamine in DBS is comparable to that in other biological matrices such as whole blood under short-term storage conditions. Lower temperatures are favourable for maintaining the integrity of the samples; however, the bloodstains must be completely dried before storing them in the refrigerator or freezer for short-term (1–7 days) to prevent hydrolytic degradation of drugs.Graphical

The Effect of Accessibility of Insoluble Substrate on the Overall Kinetics of Enzymatic Degradation

ABSTRACTThe enzymatic reaction kinetics on cellulose and other solid substrates is limited by the access of the enzyme to the reactive substrate sites. We introduce a general model in which the reaction rate is determined by the active surface area, and the resulting kinetics consequently reflects the evolving relationship between the exposed substrate surface and the remaining substrate volume. Two factors influencing the overall surface‐to‐volume ratio are considered: the shape of the substrate particles, characterized by a single numerical parameter related to its dimensionality, and the distribution of the particle sizes. The model is formulated in a form of simple analytical equations, enabling fast and efficient application to experimental data, and facilitating its incorporation into more detailed and complex models. The application of the introduced formalism exploring its potential to account for the observed reaction rate is demonstrated on two examples: the derivation of particle size distribution from experimentally determined reaction kinetics, and the prediction of reaction slowdown from experimental particle size distribution.

Additive CHARMM Force Field for Pterins and Folates.

Folates comprise a crucial class of biologically active compounds related to folic acid, playing a vital role in numerous enzymatic reactions. One-carbon metabolism, facilitated by the folate cofactor, supports numerous physiological processes, including biosynthesis, amino acid homeostasis, epigenetic maintenance, and redox defense. Folates share a common pterin heterocyclic ring structure capable of undergoing redox reactions and existing in various protonation states. This study aimed to derive molecular mechanics (MM) parameters compatible with the CHARMM36 all-atom additive force field for pterins and biologically important folates, including pterin, biopterin, and folic acid. Three redox forms were considered: oxidized, dihydrofolate, and tetrahydrofolate states. Across all protonation states, a total of 18 folates were parameterized. Partial charges were derived using the CHARMM force field parametrization protocol, based on targeting reference quantum mechanics monohydrate interactions, electrostatic potential, and dipole moment. Bonded terms were parameterized using one-dimensional adiabatic potential energy surface scans, and two-dimensional scans to parametrize in-ring torsions associated with the puckering states of dihydropterin and tetrahydropterin. The quality of the model was demonstrated through simulations of three protein complexes using optimized and initial parameters. These simulations underscored the significantly enhanced performance of the folate model developed in this study compared to the initial model without optimization in reproducing structural properties of folate-protein complexes. Overall, the presented MM model will be valuable for modeling folates in various redox states and serve as a starting point for parameterizing other folate derivatives.

Dehydrogenase versus oxidase function: the interplay between substrate binding and flavin microenvironment.

Redox enzymes, mostly equipped with metal or organic cofactors, can vary their reactivity with oxygen by orders of magnitudes. Understanding how oxygen reactivity is controlled by the protein milieu remains an open issue with broad implications for mechanistic enzymology and enzyme design. Here, we address this problem by focusing on a widespread group of flavoenzymes that oxidize phenolic compounds derived from microbial lignin degradation, using either oxygen or a cytochrome c as electron acceptors. A comprehensive phylogenetic analysis revealed conserved amino acid motifs in their flavin-binding site. Using a combination of kinetics, mutagenesis, structural, and computational methods, we examined the role of these residues. Our results demonstrate that subtle and localized changes in the flavin environment can drastically impact on oxygen reactivity. These effects are afforded through the creation or blockade of pathways for oxygen diffusion. Substrate binding plays a crucial role by potentially obstructing oxygen access to the flavin, thus influencing the enzyme's reactivity. The switch between oxidase and dehydrogenase functionalities is thereby achieved through targeted, site-specific amino acid replacements that finely tune the microenvironment around the flavin. Our findings explain how very similar enzymes can exhibit distinct functional properties, operating as oxidases or dehydrogenases. They further provide valuable insights for the rational design and engineering of enzymes with tailored functions.

A handheld biofluorometric system for acetone detection in exhaled breath condensates.

As a marker of human metabolism, acetone is important for lipid metabolism monitoring and early detection of diabetes. In this study, we developed a handheld biosensor for acetone based on fluorescence detection by utilizing the enzymatic reaction of secondary alcohol dehydrogenase (S-ADH) with β-nicotinamide adenine dinucleotide (NADH, λex = 340 nm, λem = 490 nm). In the reaction, NADH is oxidized when acetone is reduced to 2-propanol by S-ADH, and the acetone concentration can be measured by detecting the amount of NADH consumed in this reaction. First, we constructed a compact and light-weight fluorometric NADH detection system (209 g for the sensing system and 342 g for the PC), which worked using battery power. Then, sensor characteristics were evaluated after optimization of the working conditions. The developed system was able to quantify acetone in a range of 510 nM-1 mM within 1 minute. The developed battery-operated acetone biosensor demonstrated its ability to measure the acetone concentration in the exhaled breath condensate of 10 healthy subjects at rest (23.4 ± 15.1 μM) and after 16 h of fasting (37.7 ± 14.7 μM) and it distinguished the results with significant differences (p = 0.011). With the advantages of handheld portability, and high levels of sensitivity and selectivity, this sensor is expected to be widely used in clinical diagnosis and wearable biochemical sensors in the future.

Enhanced expression of Cyp17a1 and production of DHEA-S in the liver of late-pregnant rats.

Cytochrome P450 17A1 (CYP17A1) catalyzes two enzymatic reactions in the biosynthesis of dehydroepiandrosterone (DHEA) from pregnenolone. In pregnant humans, the adrenal gland is responsible for DHEA biosynthesis, which is then sulfated by SULT2A1 and released into the bloodstream. This sulfated DHEA is subsequently taken up by the placenta and deconjugated to serve as a precursor for estrogen biosynthesis. The expression of Cyp17a1 is regulated by methylation, typically showing marked interspecies differences, including repression of Cyp17a1 expression in the adrenal gland of rodents. This study focused on the liver, an extragonadal steroidogenic organ showing active sulfate conjugation, as a site for DHEA-sulfate (DHEA-S) biosynthesis during pregnancy in rodents, rather than the adrenal glands. Cyp17a1 expression in rat liver was significantly lower than in the testis, with no differences between sexes. However, Cyp17a1 expression increased significantly before parturition (gestational days [GD] 19-21) compared to late pregnancy (GD 15-18). The Sult2a family were expressed in the livers of both pregnant and non-pregnant rats. We also observed increased DHEA and DHEA-S levels in the liver of pregnant rats before parturition compared to non-pregnant rats, with DHEA-S concentrations being significantly higher at GD 19-21 than at days 15-18. These findings suggest that increased expression of Cyp17a1 in the last trimester enhances DHEA synthesis in the liver, and that DHEA is quickly conjugated by Sult2a. In rodents, the liver may be involved in DHEA-S biosynthesis before parturition, compensating for the repression of Cyp17a1 in the adrenal glands.

DORA-XGB: an improved enzymatic reaction feasibility classifier trained using a novel synthetic data approach

We outline a method for synthetically generating negative data by considering alternative reaction centers on small-molecule substrates that are known to participate in enzymatic reactions.