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1.
Int J Biol Macromol ; : 134864, 2024 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-39163969

RESUMEN

Starch, as a critical component of dough, significantly influences quality preservation during the freezing process. In particular, the fine structure of potato (B-type) starch in frozen processing is a subject of considerable interest. This study aims to investigate the intrinsic differences of B-type starch and the impact of freeze-thaw (F/T) treatment on its molecular structure and physicochemical properties. Chain length distribution and X-ray photoelectron spectroscopy were utilized to examine the structural characteristics of natural potato starch with different granule sizes. Furthermore, the fine structure, thermal properties, and rheological properties of the isolated starches after F/T treatment were analyzed. The results indicate that potato starch with smaller particle sizes exhibits higher surface CC and PO content along with a higher proportion of very short chains (DP < 6, 8.17 %) and long B chains (DP > 25, 20.68 %). The study found that after F/T treatment, the surface of small-sized starch granules was initially damaged, exhibiting threads on the surface centered on the umbilical point. Following F/T treatment, both the crystallinity (very large (VL): 24.52-18.36 %; small (S): 17.03-16.69 %) and short-range order (VL: 2.97-2.61; S: 2.71-2.35) of starch particle size decreased. Both the amylose content (20.88-14.57 %) and ΔH (10.15-8.62 J/g) of isolated starch after freeze-thaw-treated dough exhibited a decrease to varying degrees. With the exception of the fifth cycle, small-size starch particles exhibited relatively higher G' and G" values and showed significant changes as a result of F/T treatment, demonstrating high hardness and complex viscosity. Clarifying the physicochemical properties of potato starches with different granule sizes is expected to expand their applications in frozen dough.

3.
Metab Brain Dis ; 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39150655

RESUMEN

Alzheimer's disease (AD) is a neurodegenerative disorder with early autophagy deficits. Our study probed the role of lysosomal-related genes (LRGs) in AD. Using the Gene Expression Omnibus (GEO) database, we analyzed differentially expressed genes (DEGs) in AD. AD-related genes and lysosomal-related genes (LRGs) were extracted from public databases. Leveraging the UpSetR package, we identified differentially expressed LRGs (DE-LRGs). Subsequently, consensus cluster analysis was used to stratify AD patients into distinct molecular subtypes based on DE-LRGs. Immune cell patterns were studied via Single-Sample Gene Set Enrichment Analysis (ssGSEA). Molecular pathways were assessed through Gene Set Variation Analysis (GSVA), while Mendelian Randomization (MR) discerned potential gene-AD causations. To reinforce our bioinformatics findings, we conducted in vitro experiments. In total, 52 DE-LRGs were identified, with LAMP1, VAMP2, and CTSB as standout hub genes. Leveraging the 52 DE-LRGs, AD patients were categorized into three distinct molecular subtypes. Interestingly, the three aforementioned hub genes exhibited significant predictive accuracy for AD differentiation across the subtypes. The ssGSEA further illuminated correlations between LAMP1, VAMP2, and CTSB with plasma cells, fibroblasts, eosinophils, and endothelial cells. GSVA analysis underscored significant associations of LAMP1, VAMP2, and CTSB with NOTCH, TGFß, and P53 pathways. Compellingly, MR findings indicated a potential causative relationship between LAMP1, CTSB, and AD. Augmenting our bioinformatics conclusions, in vitro tests revealed that LAMP1 potentially alleviates AD progression by amplifying autophagic processes. LAMP1 and CTSB emerge as potential AD biomarkers, paving the way for innovative therapeutic interventions.

4.
Food Chem ; 460(Pt 3): 140792, 2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39126939

RESUMEN

The low bioavailability of polyphenolic compounds due to poor solubility and stability is a major challenge. Encapsulation of polyphenols in zein-based composite nanoparticles can improve the water dispersion, stability, targeted delivery, and controlled release of polyphenols in the gastrointestinal tract. In this study, we investigated the fluorescence properties, bioactivity, and microstructural characteristics of polyphenols during digestion, revealing that zein nanoparticles protect polyphenols from gastric degradation and promote their sustained release in the small intestine. The effects of different ionic species and salt ion concentrations on the digestive properties of polyphenol complex delivery systems have also been explored. In addition, the formation of "protein corona" structures during digestion may affect bioavailability. These findings highlight the potential of nanoparticle formulations to improve polyphenol stability and absorption. The results of this study may provide new insights and references for the study of polyphenol bioavailability enhancement.

5.
Foods ; 13(15)2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39123644

RESUMEN

The efficacy of many edible bioactive agents is limited by their low water dispersibility and chemical instability in foods, as well as by their poor bioaccessibility, low absorption, and metabolism within the human gastrointestinal tract. Whey proteins are amphiphilic molecules that can be used to construct a variety of edible carrier systems that can improve the performance of bioactive ingredients. These carrier systems are being used by the food and biomedical industries to encapsulate, protect, and deliver a variety of bioactive agents. In this article, we begin by providing an overview of the molecular and functional characteristics of whey proteins, and then discuss their interactions with various kinds of bioactive agents. The ability of whey proteins to be used as building blocks to assemble different kinds of carrier systems is then discussed, including nanoparticles, hydrogels, oleogels, bigels, nanofibers, nanotubes, and nanoemulsions. Moreover, applications of these carrier systems are highlighted. Different kinds of whey protein-based carriers can be used to encapsulate, protect, and deliver bioactive agents. Each kind of carrier has its own characteristics, which make them suitable for different application needs in foods and other products. Previous studies suggest that whey protein-based carriers are particularly suitable for protecting chemically labile bioactive agents and for prolonging their release profiles. In the future, it is likely that the applications of whey protein-based carriers in the food and pharmaceutical fields will expand.

6.
Int J Biol Macromol ; 276(Pt 2): 133949, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39025172

RESUMEN

Different methods of starch modification have been proposed to broaden its application. In this study, the effects of ternary mixtures of natural crosslinking agents: chitosan-betaine-vanillin and gelatin-betaine-vanillin on the properties of pea starch were explored. These combinations of substances were selected because they have complementary crosslinking mechanisms. The effects of the ternary crosslinker mixtures on the gelatinization, mechanical properties, thermal stability, and microstructure of pea starch were compared. Both combinations of crosslinkers enhanced the gelatinization viscosity, viscoelasticity, gel hardness, and thermal stability of the pea starch, by an amount that depended on the ratio of the different components in the ternary mixtures. In all cases, the crystal structure of the starch granules disappeared after gelatinization. The modified starch had a more compact and uniform microstructure than the non-modified version, especially when it was crosslinked by vanillin, gelatin, and betaine. The improvement in the gelation properties of the starch were primarily attributed to hydrogen bonding, electrostatic attraction, and Schiff base crosslinking of the various components present. Gelatin enhanced the gel strength more than chitosan, which was probably because of greater hydrogen bonding. Our findings suggest that the properties of starch can be enhanced by adding ternary mixtures of natural crosslinkers.


Asunto(s)
Benzaldehídos , Betaína , Quitosano , Reactivos de Enlaces Cruzados , Gelatina , Pisum sativum , Almidón , Gelatina/química , Almidón/química , Quitosano/química , Betaína/química , Benzaldehídos/química , Pisum sativum/química , Reactivos de Enlaces Cruzados/química , Viscosidad , Geles/química
7.
Int J Biol Macromol ; 277(Pt 1): 133960, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39029832

RESUMEN

Agarose from biomass can be used to synthesize the rare sugar 3,6-anhydro-L-galactose (L-AHG), and the new synthesis route and functional properties of L-AHG have always been the focus of research. Here we developed a novel method to co-immobilize Aga50D and BpGH117 onto streptavidin-coated magnetic nanoparticles and achieved the conversion of agarose to bioactive L-AHG in one pot. Results showed that enzymes were successfully immobilized on the carrier. The activity of co-immobilized enzymes was 2.5-fold higher than that of single immobilized enzymes. Compared with free enzymes, co-immobilized enzymes exhibited enhanced thermal stability. The co-immobilized enzymes retained 79.45 % relative activity at 40 °C for 3 h, while the free enzymes only possessed 21.40 % residual activity. After eight cycles, the co-immobilized enzymes still retained 73.47 % of the initial activity. After silica gel chromatography, the purity of L-AHG obtained by co-immobilized enzymes hydrolysis reached 83.02 %. Furthermore, bioactivity experiments demonstrated that L-AHG displayed better antioxidant and antibacterial effects than neoagarobiose. L-AHG had broad-spectrum antibacterial activity, while neoagarobiose and D-galactose did not show an obvious antibacterial effect. This study provides a feasible method for the production of L-AHG by a co-immobilized multi-enzyme system and confirms that L-AHG plays a key role in the bioactivity of neoagarobiose.

8.
Chem Commun (Camb) ; 60(61): 7906-7909, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-38979947

RESUMEN

This report describes a copper-catalyzed, photoinduced N-to-alkyl radical relay Sonogashira-type reactions at benzylic sites in o-alkylbenzamides with alkynes. The process employs an N-to-alkyl radical mechanism, initiated through the copper-catalyzed reductive generation of nitrogen radicals. Radical translocation is facilitated by a 1,5-hydrogen atom transfer (1,5-HAT), leading to the formation of translocated carbon radicals. These radicals are then subjected to copper-catalyzed alkynylation. The methodology exhibits broad sub-strate scope and applicability to the synthesis of complex natural products.

9.
Appl Opt ; 63(12): 3299-3303, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38856481

RESUMEN

Integration of resonators impacts the utilization of the 3-µm-thick silicon-on-insulator (SOI) platform in photonics integrated circuits (PICs). We propose an integrated resonator leveraging a deep-etch silicon waveguide. Through the utilization of a tunable coupler based on multimode interferometers (MMIs), the resonator achieves high fabrication tolerance and reconfigurability. In a critical-coupling state, it serves as a filter with an extinction ratio (ER) of 23.5 dB and quality (Q) factor of 3.1×105, operating within the range of 1530-1570 nm. In an extreme over-coupling state, it functions as a large-bandwidth delay line, offering continuous change in delay time of 22 ps, nearly wavelength-independent. This work provides devices to the 3-µm-thick silicon photonics device library, enriching the potential applications of this technology platform.

10.
Phenomics ; 4(2): 187-202, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38884059

RESUMEN

The Shroom (Shrm) family of actin-binding proteins has a unique and highly conserved Apx/Shrm Domain 2 (ASD2) motif. Shroom protein directs the subcellular localization of Rho-associated kinase (ROCK), which remodels the actomyosin cytoskeleton and changes cellular morphology via its ability to phosphorylate and activate non-muscle myosin II. Therefore, the Shrm-ROCK complex is critical for the cellular shape and the development of many tissues, including the neural tube, eye, intestines, heart, and vasculature system. Importantly, the structure and expression of Shrm proteins are also associated with neural tube defects, chronic kidney disease, metastasis of carcinoma, and X-link mental retardation. Therefore, a better understanding of Shrm-mediated signaling transduction pathways is essential for the development of new therapeutic strategies to minimize damage resulting in abnormal Shrm proteins. This paper provides a comprehensive overview of the various Shrm proteins and their roles in morphogenesis and disease.

11.
Langmuir ; 40(20): 10769-10775, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38720176

RESUMEN

The icing of propellers is a critical factor that affects the safe operation of aircraft. A superhydrophobic surface, with its extremely low wettability, is highly valuable in the field of anti-icing. This study investigates the distribution pattern of ice on propeller surfaces by employing spray coating to create superhydrophobic surfaces. Additionally, it conducts a comparative analysis of thrust and power under icing and non-icing conditions to comprehensively assess the impact of superhydrophobic surfaces on propeller operation efficiency. The results show that superhydrophobic surfaces not only diminish the ice formation area on propeller surfaces but also enhance the traction of propellers under icing conditions, reducing the power consumption of the propeller. The generated thrust can reach up to 1.6 times that of non-superhydrophobic propellers while consuming only one-third of the power. Furthermore, under non-icing conditions, superhydrophobic surfaces exhibit minimal impact on propeller performance.

12.
Int J Biol Macromol ; 269(Pt 2): 131967, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38692528

RESUMEN

The development of food-grade high internal phase emulsions (HIPEs) for 3D printing and the replacement of animal fats have attracted considerable attention. In this study, in order to improve the rheological properties and stability of pea protein to prepare HIPE, pea protein/carboxymethyl cellulose (pH-PP/CMC) was prepared and subjected to pH cycle treatment to produce HIPEs. The results showed that pH cycle treatment and CMC significantly reduced the droplet size of HIPEs (from 143.33 to 12.10 µm). At higher CMC concentrations, the interfacial tension of the PP solution decreased from 12.84 to 11.71 mN/m without pH cycle treatment and to 10.79 mN/m with pH cycle treatment. The HIPEs with higher CMC concentrations subjected to pH cycle treatment showed shear thinning behavior and higher viscoelasticity and recovered their solid-like properties after being subjected to 50 % strain, indicating that they could be used for 3D printing. The 3D printing results showed that the pH-PP/CMC HIPE with 0.3 % CMC had the finest structure. Our work provides new insights into developing food-grade HIPEs and facilitating their use in 3D printing inks as nutrient delivery systems and animal fat substitutes.


Asunto(s)
Carboximetilcelulosa de Sodio , Emulsiones , Proteínas de Guisantes , Impresión Tridimensional , Reología , Carboximetilcelulosa de Sodio/química , Concentración de Iones de Hidrógeno , Emulsiones/química , Proteínas de Guisantes/química , Viscosidad
13.
Foodborne Pathog Dis ; 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38608217

RESUMEN

This study aimed to assess the clinical characteristics, treatment, and prognosis of osteoarticular brucellosis. We conducted a retrospective study enrolling brucellosis patients from the Sixth People's Hospital of Shenyang between September 2014 and June 2019. A total of 1917 participants were admitted during this period. After applying propensity score matching, we retrospectively analyzed 429 patients with osteoarthritis and 429 patients without osteoarthritis. The primary outcome was treatment completion. The secondary outcome was symptom disappearance and seroconversion. Brucellosis patients with osteoarthritis had longer treatment course (160 [134.3-185.7] vs. 120 [102.3-137.7] d, p = 0.008) than those without osteoarthritis. The most common involved site was lumbar vertebrae (290 [67.6%]) in brucellosis patients with osteoarthritis. Longer symptom duration (90 [83.0-97.0] vs. 42 [40.2-43.8], p < 0.001) along with no significant difference in seroconversion (180 [178.8-181.2] vs. 180 [135.1-224.9], p = 0.212) was observed in osteoarthritis patients with treatment course >90 d. Peripheral joint involvement (adjusted hazard ratio [95% confidence interval] 1.485 [1.103-1.999]; p = 0.009) had a shorter symptom duration compared with shaft joint involvement. No significant differences were observed in treatment therapy between doxycycline plus rifampin (DR) or plus cephalosporins (DRC) in treatment course (p = 0.190), symptom persistence (p = 0.294), and seroconversion (p = 0.086). Lumbar vertebra was the most commonly involved site. Even if all symptoms disappeared, Serum agglutination test potentially remained positive in some patients. Compared with peripheral arthritis, shaft arthritis was the high-risk factor for longer symptom duration. The therapeutic effects were similar between DR and DRC. In summary, our study provided important insights into the clinical characteristics, treatment, and outcomes of osteoarticular brucellosis. Clinical Trial Registration number: NCT04020536.

14.
Food Chem ; 451: 139477, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38678664

RESUMEN

In this study, a combination of whey protein (hydrophilic coating) and polydopamine (crosslinking agent) was used to improve the stability and functionality of quercetin-loaded zein nanoparticles. There are two key benefits of the core-shell nanoparticles formed. First, the ability of the polydopamine to bind to both zein and whey protein facilitates the formation of a stable core-shell structure, thereby protecting quercetin from any pro-oxidants in the aqueous surroundings. Second, neutral and hydrophilic whey proteins were used for the surface coating of the nanoparticles to further enhance the sustained and slow release of quercetin, facilitating its sustained release into the body at a slow and steady rate. The results of this study will promote the innovative development of precise nutritional delivery systems for zein and provide a theoretical basis for the design and development of dietary supplements based on hydrophobic food nutrient molecules.


Asunto(s)
Interacciones Hidrofóbicas e Hidrofílicas , Indoles , Nanopartículas , Polímeros , Zeína , Zeína/química , Indoles/química , Polímeros/química , Nanopartículas/química , Proteína de Suero de Leche/química , Quercetina/química , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos
15.
Mol Cell Proteomics ; 23(6): 100769, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38641227

RESUMEN

The understanding of dynamic plasma proteome features in hybrid immunity and breakthrough infection is limited. A deeper understanding of the immune differences between heterologous and homologous immunization could assist in the future establishment of vaccination strategies. In this study, 40 participants who received a third dose of either a homologous BBIBP-CorV or a heterologous ZF2001 protein subunit vaccine following two doses of inactivated coronavirus disease 2019 vaccines and 12 patients with BA2.2 breakthrough infections were enrolled. Serum samples were collected at days 0, 28, and 180 following the boosting vaccination and breakthrough and then analyzed using neutralizing antibody tests and mass spectrometer-based proteomics. Mass cytometry of peripheral blood mononuclear cell samples was also performed in this cohort. The chemokine signaling pathway and humoral response markers (IgG2 and IgG3) associated with infection were found to be upregulated in breakthrough infections compared to vaccination-induced immunity. Elevated expression of IGKV, IGHV, IL-17 signaling, and the phagocytosis pathway, along with lower expression of FGL2, were correlated with higher antibody levels in the boosting vaccination groups. The MAPK signaling pathway and Fc gamma R-mediated phagocytosis were more enriched in the heterologous immunization groups than in the homologous immunization groups. Breakthrough infections can trigger more intensive inflammatory chemokine responses than vaccination. T-cell and innate immune activation have been shown to be closely related to enhanced antibody levels after vaccination and therefore might be potential targets for vaccine adjuvant design.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Proteómica , SARS-CoV-2 , Humanos , Proteómica/métodos , COVID-19/prevención & control , COVID-19/inmunología , SARS-CoV-2/inmunología , Femenino , Vacunas contra la COVID-19/inmunología , Vacunas contra la COVID-19/administración & dosificación , Masculino , Estudios Longitudinales , Adulto , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/sangre , Persona de Mediana Edad , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Inmunización Secundaria , Vacunación , Estudios de Cohortes , Proteoma , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Infección Irruptiva
16.
Int J Biol Macromol ; 262(Pt 1): 129940, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38320637

RESUMEN

Konjac glucomannan (KGM) has been widely used to deliver bioactive components due to its naturalness, non-toxicity, excellent biodegradability, biocompatibility, and other characteristics. This review presents an overview of konjac glucomannan as a matrix, and the types of konjac glucomannan-based delivery systems (such as hydrogels, food packaging films, microencapsulation, emulsions, nanomicelles) and their construction methods are introduced in detail. Furthermore, taking polyphenol compounds, probiotics, flavor substances, fatty acids, and other components as representatives, the applied research progress of konjac glucomannan-based delivery systems in food are summarized. Finally, the prospects for research directions in konjac glucomannan-based delivery systems are examined, thereby providing a theoretical basis for expanding the application of konjac glucomannan in other industries, such as food and medicine.


Asunto(s)
Hidrogeles , Mananos
17.
Micromachines (Basel) ; 15(2)2024 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-38399013

RESUMEN

The exceptional performance of graphene has driven the advancement of its preparation techniques and applications. Laser-induced graphene (LIG), as a novel graphene preparation technique, has been applied in various fields. Graphene periodic structures created by the LIG technique exhibit superhydrophobic characteristics and can be used for deicing and anti-icing applications, which are significantly influenced by the laser parameters. The laser surface treatment process was simulated by a finite element software analysis (COMSOL Multiphysics) to optimize the scanning parameter range, and the linear array surface structure was subsequently fabricated by the LIG technique. The generation of graphene was confirmed by Raman spectroscopy and energy-dispersive X-ray spectroscopy. The periodic linear array structure was observed by scanning electron microscopy (SEM) and confocal laser imaging (CLSM). In addition, CLSM testings, contact angle measurements, and delayed icing experiments were systematically performed to investigate the effect of scanning speed on surface hydrophobicity. The results show that high-quality and uniform graphene can be achieved using the laser scanning speed of 125 mm/s. The periodic linear array structures can obviously increase the contact angle and suppress delayed icing. Furthermore, these structures have the enhanced ability of the electric heating deicing, which can reach 100 °C and 240 °C within 15 s and within 60 s under the DC voltage power supply ranging from 3 to 7 V, respectively. These results indicate that the LIG technique can be developed to provide an efficient, economical, and convenient approach for preparing graphene and that the hydrophobic surface array structure based on LIG has considerable potential for deicing and anti-icing applications.

18.
Nat Commun ; 15(1): 1835, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38418488

RESUMEN

B- and T-lymphocyte attenuator (BTLA) levels are increased in patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). This condition is characterized by susceptibility to infection and T-cell immune exhaustion. However, whether BTLA can induce T-cell immune exhaustion and increase the risk of infection remains unclear. Here, we report that BTLA levels are significantly increased in the circulating and intrahepatic CD4+ T cells from patients with HBV-ACLF, and are positively correlated with disease severity, prognosis, and infection complications. BTLA levels were upregulated by the IL-6 and TNF signaling pathways. Antibody crosslinking of BTLA activated the PI3K-Akt pathway to inhibit the activation, proliferation, and cytokine production of CD4+ T cells while promoting their apoptosis. In contrast, BTLA knockdown promoted their activation and proliferation. BTLA-/- ACLF mice exhibited increased cytokine secretion, and reduced mortality and bacterial burden. The administration of a neutralizing anti-BTLA antibody reduced Klebsiella pneumoniae load and mortality in mice with ACLF. These data may help elucidate HBV-ACLF pathogenesis and aid in identifying novel drug targets.


Asunto(s)
Insuficiencia Hepática Crónica Agudizada , Hepatitis B Crónica , Animales , Humanos , Ratones , Insuficiencia Hepática Crónica Agudizada/complicaciones , Linfocitos T CD4-Positivos , Citocinas/metabolismo , Hepatitis B Crónica/complicaciones , Fosfatidilinositol 3-Quinasas , Receptores Inmunológicos/metabolismo , Agotamiento de Células T
19.
Int J Biol Macromol ; 261(Pt 1): 129807, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38290635

RESUMEN

ß-Agarase was biotinylated and immobilized onto streptavidin-conjugated magnetic nanoparticles to provide insights into the effect of immobilization sites on ß-agarase immobilization. Results showed that, compared with free enzyme, the stability of prepared immobilized ß-agarases through amino or carboxyl activation were both significantly improved. However, the amino-activated immobilized ß-agarase showed higher thermostability and catalytic efficiency than the carboxyl-activated immobilized ß-agarase. The relative activity of the former was 65.00 % after incubation at 50 °C for 1 h, which was 1.77-fold higher than that of the latter. Additionally, amino-activated immobilization increased the affinity of the enzyme to the substrate, and its maximum reaction rate (0.68 µmol/min) was superior to that of carboxyl-activated immobilization (0.53 µmol/min). The visualization results showed that the catalytic site of ß-agarase after carboxyl-activated immobilization was more susceptible to the immobilization process, and the orientation of the enzyme may also hinder substrate binding and product release. These results suggest that by pre-selecting appropriate activation sites and enzyme orientation, immobilized enzymes with higher catalytic activity and stability can be obtained, making them more suitable for the application of continuous production.


Asunto(s)
Biotina , Enzimas Inmovilizadas , Estreptavidina , Enzimas Inmovilizadas/metabolismo , Glicósido Hidrolasas/metabolismo , Estabilidad de Enzimas
20.
Int J Biol Macromol ; 260(Pt 1): 129506, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38244735

RESUMEN

Alginate is mainly a linear polysaccharide composed of randomly arranged ß-D-mannuronic acid and α-L-guluronic acid linked by α, ß-(1,4)-glycosidic bonds. Alginate lyases degrade alginate mainly adopting a ß-elimination mechanism, breaking the glycosidic bonds between the monomers and forming a double bond between the C4 and C5 sugar rings to produce alginate oligosaccharides consisting of 2-25 monomers, which have various physiological functions. Thus, it can be used for the continuous industrial production of alginate oligosaccharides with a specific degree of polymerization, in accordance with the requirements of green exploitation of marine resources. With the development of structural analysis, the quantity of characterized alginate lyase structures is progressively growing, leading to a concomitant improvement in understanding the catalytic mechanism. Additionally, the use of molecular modification methods including rational design, truncated expression of non-catalytic domains, and recombination of conserved domains can improve the catalytic properties of the original enzyme, enabling researchers to screen out the enzyme with the expected excellent performance with high success rate and less workload. This review presents the latest findings on the catalytic mechanism of alginate lyases and outlines the methods for molecular modifications. Moreover, it explores the connection between the degree of polymerization and the physiological functions of alginate oligosaccharides, providing a reference for enzymatic preparation development and utilization.


Asunto(s)
Alginatos , Polisacárido Liasas , Alginatos/química , Polisacárido Liasas/química , Oligosacáridos/metabolismo , Polisacáridos , Especificidad por Sustrato
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