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A Novel cold-active chitin deacetylase from Shewanella psychrophila WP2 (SpsCDA) was overexpressed in Escherichia coli BL21 and employed for deacetylation of chitin to chitosan. The produced chitosan was characterized, and its antifungal activity was investigated against Fusarium oxysporum. The purified recombinant SpsCDA appeared as a single band on SDS-PAGE at approximately 60 kDa, and its specific activity was 92 U/mg. The optimum temperature and pH of SpsCDA were 15 °C and 8.0, respectively, and the enzyme activity was significantly enhanced in the presence of NaCl. The bioconversion of chitin to chitosan by SpsCDA was accomplished in 72 h, and the chitosan yield was 69.2%. The solubility of chitosan was estimated to be 73.4%, and the degree of deacetylation was 78.1%. The estimated molecular weight of the produced chitosan was 224.7 ± 8.4 kDa with a crystallinity index (CrI) value of 18.75. Moreover, FTIR and XRD spectra revealed the characteristic peaks for enzymatically produced chitosan compared with standard chitosan, indicating their structural similarity. The produced chitosan inhibited spore germination of F. oxysporum with a minimum inhibitory concentration (MIC) of 1.56 mg/mL. The potential antifungal effect of chitosan is attributed to the inhibition of spore germination accompanied by ultrastructural damage of membranes and leakage of cellular components, as evidenced by transmission electron microscopy (TEM), and accumulation of reactive oxygen species (ROS) that was confirmed by fluorescence microscopy. This study shed light on the cold-active chitin deacetylase from S. psychrophila and provides a candidate enzyme for the green preparation of chitosan. [ABSTRACT FROM AUTHOR]

Lysine deacetylases (KDACs or HDACs) are metal‐dependent enzymes that regulate lysine acetylation, a post‐translational modification that is present on thousands of human proteins, essential for many cellular processes, and often misregulated in diseases. The selective inhibition of KDACs would allow for understanding of the biological roles of individual KDACs and therapeutic targeting of individual enzymes. Recent studies have suggested that purportedly specific KDAC inhibitors have significant off‐target binding, but the biological consequences of off‐target binding were not evaluated. We compared the effects of treatment with two of the reportedly most KDAC‐selective inhibitors, Tubastatin A and PCI‐34051, in HT1080 cells in which the endogenous KDAC6 or KDAC8 gene has been mutated to inactivate enzyme catalysis while retaining enzyme expression. Genetic inactivation results in much stronger deacetylation defects on known targets compared to inhibitor treatment. Gene expression analysis revealed that both inhibitors have extensive and extensively overlapping off‐target effects in cells, even at low inhibitor doses. Furthermore, Tubastatin A treatment led to increased histone acetylation, while inactivation of KDAC6 or KDAC8 did not. Genetic inactivation of KDAC6, but not KDAC8, impaired tumor formation in a xenograft model system, in contrast to previous reports with KDAC inhibitors suggesting the reverse. We conclude that the majority of observed biological effects of treatment with KDAC inhibitors are due to off‐target effects rather than the intended KDAC inhibition. Developing a truly specific KDAC6 inhibitor could be a promising therapeutic avenue, but it is imperative to develop new inhibitors that selectively mimic genetic inactivation of individual KDACs. [ABSTRACT FROM AUTHOR]

This review examines key journal articles on the isolation of chitin from mushroom biomass comparing these findings to those related to crustacean chitin. It highlights the need for standardizing chitin characterization, emphasizing that chitin comprises a family of polymers with variations in molecular weight (Mw), degree of acetylation (%DA), and acetylation patterns (P A), leading to diverse physicochemical properties and biological activities. The review positions fungi and mushrooms as emerging sources of 'vegan' chitin, being non-animal and free from allergenic proteins. Their ability to be cultivated year-round, along with rapid growth and low-cost biowaste substrates, makes them attractive alternatives to crustacean chitin. Market adoption of mushroom chitin will depend on its potential applications in high-value products. Traditionally, chitin characterization has been semi-qualitative, but there is now a growing recognition of how sample inconsistencies impact research quality. This review underscores the importance of quantitative analysis for achieving practical, repeatable, and reproducible results while addressing the challenges in characterizing fungal chitin. We argue that accurately determining the properties of fungal chitin is essential and should be a fundamental aspect of every study, as these properties significantly influence the polymer's characteristics and biological activity. [ABSTRACT FROM AUTHOR]

The subcellular localization of Yes-associated protein (YAP) is dynamically regulated by post-transcriptional modifications, critically influencing cardiac function. Despite its significance, the precise mechanism controlling YAP nuclear sequestration and its role in cardiac hypertrophy remain poorly defined. In this study, utilizing immunoprecipitation-mass spectrometry, we identified potential acetylation sites and interacting proteins of YAP. Co-immunoprecipitation and immunofluorescence assays were used to elucidate the protein interactions and subcellular colocalization. We found that YAP protected against ISO-induced pathological cardiac hypertrophy both in vivo and in vitro. During cardiac hypertrophy YAP acetylation increased while its nuclear accumulation reduced without altering Ser127 phosphorylation. Notably, lysine 236 was identified as a novel acetylation site on YAP. Acetylation at K236 facilitated YAP's nucleic export, suppressed the expression of target genes such as NRF1 and Cox IV, and counteracted YAP's anti-hypertrophic effects. Importantly, deacetylase SIRT6 was identified as a regulator of YAP deacetylation, disrupting the YAP with chaperone protein 14–3–3 interaction and inhibiting YAP's nuclear export, thereby facilitating cardiac protective role of YAP. This study identified YAP K236 acetylation as a key regulator of its nuclear retention in cardiomyocytes, with SIRT6-mediated deacetylation facilitating YAP's protective effects against cardiac hypertrophy. Targeting YAP acetylation may offer a promising therapeutic strategy for cardiac hypertrophy. [Display omitted] • YAP acetylation during cardiac hypertrophy correlates with its nuclear export. • Lysine 236 residue is identified as a novel acetylated site, and increased acetylation at this site promotes nucleic export, offsetting its anti-hypertrophic effects. • SIRT6 deacetylates YAP, enhances its nucleic localization by disrupting the interaction with 14–3–3 chaperone protein, and facilitates its protective role against cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

The effect of different degrees of deacetylation (DDs) of deacetylated konjac glucomannan (DKGM) on the gluten structure, water state, and yeast activity of frozen dough was evaluated. The moderate DKGM group maintained a more continuous gluten network after three freeze-thaw cycles, as evidenced by an 8.67% increase in disulfide bond content and a 15.01% increase in α-helix content compared to the KGM group. DKGM effectively impeded bound water migration, with the moderate DKGM group retaining 8.28% more bound water than the KGM group after three freeze-thaw cycles. The stabilization of gluten structure and water state in frozen dough by DKGM resulted in higher yeast activity in the low and moderate deacetylation groups (DD = 31.31% and 50.24%). Additionally, DKGM enhanced the quality of frozen steamed bread. The results indicate that DKGM with a moderate DD (50.24%) effectively alleviates the quality deterioration of frozen dough. These findings suggest that DKGM has great potential as a novel cryoprotectant for frozen dough, with DD being a crucial factor in its cryoprotective effect. [Display omitted] • Moderate DD (50.24%) of DKGM reduced quality loss in frozen dough. • Moderate DD of DKGM enhanced gluten structure in frozen dough. • DKGM inhibited water migration during freeze-thaw cycles. • DKGM with moderate DD improved yeast activity in frozen dough. • DKGM improved specific volume and texture of steamed bread from frozen dough. [ABSTRACT FROM AUTHOR]

Objective: Post-resuscitation brain injury is a common sequela after cardiac arrest (CA). Increasing sirtuin1 (SIRT1) has been involved in neuroprotection in oxygen-glucose deprivation (OGD) neurons, and we investigated its mechanism in post-cardiopulmonary resuscitation (CPR) rat brain injury by mediating p65 deacetylation modification to mediate hippocampal neuronal ferroptosis., Methods: Sprague-Dawley rat CA/CPR model was established and treated with Ad-SIRT1 and Ad-GFP adenovirus vectors, or Erastin. Rat postoperative neurological function, and cognitive and learning abilities were assessed by neurological deficit score and Morris water maze test. Hippocampal neuronal pathological changes and injury were evaluated by H&E and TUNEL staining. Serum brain injury biomarkers and hippocampal inflammatory factors and SIRT1 mRNA levels were determined by ELISA and RT-qPCR. OGD/reoxygenation (OGD/R) rat hippocampal neuron (H19-7) model was established. Cell viability and injury, nuclear factor-kappa B (NF-κB) p65 localization, iron content, and levels of glutathione, malondialdehyde, reactive oxygen species, SIRT1, Ac NF-κB p65 (Lys310), NF-κB p65, ACSL4, glutathione peroxidase 4 and SLC7A11 were measured., Results: In CA/CPR rats, SIRT1 was down-regulated, and SIRT1 overexpression alleviated cerebral injury. SIRT1 overexpression inhibited OGD/R-induced H19-7 cell ferroptosis to ameliorate cell injury, and inactivated the NF-κB pathway by reducing p65 acetylation to hinder its entry into the nucleus. Inactivating the NF-κB pathway reduced OGD/R-induced ferroptosis and alleviated cell injury. SIRT1 alleviated cerebral injury by mediating p65 deacetylation to inhibit hippocampal neuronal ferroptosis mediated by the NF-κB pathway., Conclusions: SIRT1 inhibited the NF-κB signaling pathway-mediated hippocampal neuronal ferroptosis by mediating p65 deacetylation modification, thereby alleviating brain injury in CA/CPR rats., Competing Interests: Declarations. Ethics Statement: All animal experimental protocols and procedures in this study were approved by the Animal Ethics Committee of Kunming Medical University(Ethics approval document number: kmmu20220412) and strictly adhered to the approved agreement. Great efforts were made to minimize the number of animals and to reduce their suffering. Submission Declaration and Verification: The work presented in this study has not been previously published, is not being considered for publication elsewhere, has been approved for publication by all authors and the relevant authorities, and will not be published in any other form without consent. Consent for Publication: Not applicable. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Dysregulated energy metabolism, particularly lipid metabolism disorders, has been identified as a key factor in the development of diabetic cardiomyopathy (DCM). Sirtuin 2 (SIRT2) is a deacetylase involved in the regulation of metabolism and cellular energy homeostasis, yet its role in the progression of DCM remains unclear. We observed significantly reduced SIRT2 expression in DCM model mice. Cardiac-specific overexpression of SIRT2 protected mice from streptozotocin/high-fat diet (STZ/HFD)-induced insulin resistance (IR), cell apoptosis, and cardiac dysfunction, whereas its downregulation exacerbated these conditions. Moreover, we found that SIRT2 regulated cardiac lipid accumulation and fatty acid oxidation (FAO), and identified its localization in cardiac mitochondria. Mechanistically, we determined carnitine palmitoyltransferase 2 (CPT2) as a critical substrate of SIRT2, which is implicated in DCM. SIRT2-mediated deacetylation at K239 enhanced CPT2 ubiquitination, resulting in decreased protein stability and subsequent inhibition of FAO and reactive oxygen species (ROS) production. Taken together, these findings suggest that the SIRT2/CPT2 signaling pathway plays a crucial role in DCM progression., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

As a hallmark of cancer, metabolic reprogramming adjusts macromolecular synthesis, energy metabolism and redox homeostasis processes to adapt to and promote the complex biological processes of abnormal growth and proliferation. The complexity of metabolic reprogramming lies in its precise regulation by multiple levels and factors, including the interplay of multiple signalling pathways, precise regulation of transcription factors and dynamic adjustments in metabolic enzyme activity. In this complex regulatory network, acetylation and deacetylation, which are important post-translational modifications, regulate key molecules and processes related to metabolic reprogramming by affecting protein function and stability. Dysregulation of acetylation and deacetylation may alter cancer cell metabolic patterns by affecting signalling pathways, transcription factors and metabolic enzyme activity related to metabolic reprogramming, increasing the susceptibility to rapid proliferation and survival. In this review, we focus on discussing how acetylation and deacetylation regulate cancer metabolism, thereby highlighting the central role of these post-translational modifications in metabolic reprogramming, and hoping to provide strong support for the development of novel cancer treatment strategies. KEY POINTS: Protein acetylation and deacetylation are key regulators of metabolic reprogramming in tumour cells. These modifications influence signalling pathways critical for tumour metabolism. They modulate the activity of transcription factors that drive gene expression changes. Metabolic enzymes are also affected, altering cellular metabolism to support tumour growth., (© 2025 The Author(s). Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.)