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Alzheimer's Research & Therapy May 2023The purpose of this study was to evaluate cholesterol esterification and HDL subclasses in plasma and cerebrospinal fluid (CSF) of Alzheimer's disease (AD) patients.
OBJECTIVE
The purpose of this study was to evaluate cholesterol esterification and HDL subclasses in plasma and cerebrospinal fluid (CSF) of Alzheimer's disease (AD) patients.
METHODS
The study enrolled 70 AD patients and 74 cognitively normal controls comparable for age and sex. Lipoprotein profile, cholesterol esterification, and cholesterol efflux capacity (CEC) were evaluated in plasma and CSF.
RESULTS
AD patients have normal plasma lipids but significantly reduced unesterified cholesterol and unesterified/total cholesterol ratio. Lecithin:cholesterol acyltransferase (LCAT) activity and cholesterol esterification rate (CER), two measures of the efficiency of the esterification process, were reduced by 29% and 16%, respectively, in the plasma of AD patients. Plasma HDL subclass distribution in AD patients was comparable to that of controls but the content of small discoidal preβ-HDL particles was significantly reduced. In agreement with the reduced preβ-HDL particles, cholesterol efflux capacity mediated by the transporters ABCA1 and ABCG1 was reduced in AD patients' plasma. The CSF unesterified to total cholesterol ratio was increased in AD patients, and CSF CER and CEC from astrocytes were significantly reduced in AD patients. In the AD group, a significant positive correlation was observed between plasma unesterified cholesterol and unesterified/total cholesterol ratio with Aβ CSF content.
CONCLUSION
Taken together our data indicate that cholesterol esterification is hampered in plasma and CSF of AD patients and that plasma cholesterol esterification biomarkers (unesterified cholesterol and unesterified/total cholesterol ratio) are significantly associated to disease biomarkers (i.e., CSF Aβ).
Topics: Humans; Alzheimer Disease; Esterification; High-Density Lipoproteins, Pre-beta; Cholesterol; Biomarkers
PubMed: 37210544
DOI: 10.1186/s13195-023-01241-6 -
Ultrasonics Sonochemistry Nov 2014Ultrasound accelerates the free fatty acids esterification rate by reducing the mass transfer resistance between methanol in the liquid phase and absorbed organic...
Ultrasound accelerates the free fatty acids esterification rate by reducing the mass transfer resistance between methanol in the liquid phase and absorbed organic species on Amberlyst®46 catalyst. The reaction rates of canola oil is three times greater than for tobacco seed oil but half the reaction rate of pure oleic acid as measured in a batch reactor. The beneficial effects of ultrasound vs. the conventional approach are more pronounced at lower temperatures (20°C and 40°C vs. 63°C): at 20°C, the free fatty acids conversion reaches 68% vs. 23% with conventional mechanical stirring. The increased conversion is attributed to acoustic cavitation that increases mass transfer in the vicinity of the active sites. The Eley-Rideal kinetic model in which the concentration of the reacting species is expressed taking into account the mass transfer between the phases is in excellent agreement with the experimental data. Ultrasound increases the mass transfer coefficient in the tobacco oil 6 and 4.1 fold at 20°C and 40°C, respectively.
Topics: Esterification; Fatty Acids, Monounsaturated; Fatty Acids, Nonesterified; Kinetics; Methanol; Plant Oils; Rapeseed Oil; Nicotiana
PubMed: 24534067
DOI: 10.1016/j.ultsonch.2014.01.026 -
Molecular Plant Sep 2009The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated... (Review)
Review
The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated during development. The pectic polysaccharide homogalacturonan is a major component of the plant primary walls. Biosynthesis and in muro modification of homogalacturonan have recently emerged as key determinants of plant development, controlling cell adhesion, organ development, and phyllotactic patterning. This review will focus on recent findings regarding impact of homogalacturonan content and methyl-esterification status of this polymer on plant life. De-methyl-esterification of homogalacturonan occurs through the action of the ubiquitous enzyme 'pectin methyl-esterase'. We here describe various strategies developed by the plant to finely tune the methyl-esterification status of homogalacturonan along key events of the plant lifecycle.
Topics: Carbohydrate Metabolism; Cell Wall; Esterification; Models, Biological; Pectins; Plant Development; Plants
PubMed: 19825662
DOI: 10.1093/mp/ssp066 -
Molecules (Basel, Switzerland) Mar 2020An esterification and amination of benzylic C-H bonds was developed by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) under metal- and iodide-free conditions....
An esterification and amination of benzylic C-H bonds was developed by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) under metal- and iodide-free conditions. Both carboxylic acids and amines could be used as ideal coupling partners for the oxidative coupling reactions with various diarylmethanes. A close to equal amount of coupling reagents was enough to afford the product in good to high yields.
Topics: Amination; Amines; Benzhydryl Compounds; Benzoquinones; Carboxylic Acids; Esterification; Models, Chemical; Oxidation-Reduction
PubMed: 32230851
DOI: 10.3390/molecules25071527 -
International Journal of Molecular... Feb 2022lipase B () enzyme was encapsulated and cross-linked by silica matrix to enhance its thermal stability and reusability, and demonstrated an enzymatic ability for rapid...
lipase B () enzyme was encapsulated and cross-linked by silica matrix to enhance its thermal stability and reusability, and demonstrated an enzymatic ability for rapid hydrolysis and esterification. Silica encapsulated CalB particles (Si-E-CPs) and silica cross-linked CalB particles (Si-CL-CPs) were prepared as a function of TEOS concentration. The particle size analysis, thermal stability, catalytic activity in different pHs, and reusability of Si-E-CPs and Si-CL-CPs were demonstrated. Furthermore, the determination of the CalB enzyme in Si-E-CPs and Si-CL-CPs was achieved by Bradford assay and TGA analysis. Enzymatic hydrolysis was performed against the -nitrophenyl butyrate and the catalytic parameters (K, V, and K) were calculated by the Michaelis-Menten equation and a Lineweaver-Burk plot. Moreover, enzymatic synthesis for benzyl benzoate was demonstrated by esterification with an acyl donor of benzoic acid and two acyl donors of benzoic anhydride. Although the conversion efficiency of Si-CL-CPs was not much higher than that of native CalB, it has an efficiency of 91% compared to native CalB and is expected to be very useful because it has high thermal and pH stability and excellent reusability.
Topics: Ceramics; Enzymes, Immobilized; Esterification; Fungal Proteins; Hydrolysis; Lipase; Silicon Dioxide
PubMed: 35269598
DOI: 10.3390/ijms23052459 -
Biotechnology Advances Oct 2022After several decades during which proteases and after lipases took the biotransformation world scene as the predominant biocatalysts, a new, promising enzyme was... (Review)
Review
After several decades during which proteases and after lipases took the biotransformation world scene as the predominant biocatalysts, a new, promising enzyme was discovered and characterized. The acyltransferase from Mycobacterium smegmatis (MsAcT) has in fact an extraordinary activity for a wide array of reactions, such as trans-esterification, amidation, trans-amidation and perhydrolysis, both in water and solvent media, giving rise to a series of interesting compounds including APIs (i.e., active pharmaceutical ingredients), natural flavors and fragrances, monomers for polymer synthesis, and peracids employed as disinfectants or antimicrobials. Although the most used acylating agent has been ethyl acetate (EtOAc), depending on the reaction type also acetamide, dimethyl carbonate and a variety of other esters, have been reported. The best yields were reached using very reactive donors such as vinyl or isopropenyl esters (almost complete conversion in rapid reaction times and water media for condensation reactions). In this review article the most innovative scientific advances on MsAcT, its mechanism and engineering are summarized, putting a particular focus on the different kind of processes (batch and flow) that it is possible to carry out using this enzyme as free or immobilized form. In conclusion, the author personal view on the unexplored reaction possibilities using MsAcT is reported as a window on the future of the topic.
Topics: Acyltransferases; Biocatalysis; Enzymes, Immobilized; Esterification; Esters; Mycobacterium smegmatis; Water
PubMed: 35609801
DOI: 10.1016/j.biotechadv.2022.107985 -
The Plant Cell Dec 2019
Topics: Bread; Esterases; Esterification; Lipase; Lutein; Triticum
PubMed: 31578226
DOI: 10.1105/tpc.19.00768 -
Journal of Oleo Science 2022Castor oil is a vegetable product extracted from Ricinus communis L (castor seed), which is primarily considered an important commercial value for the manufacturing of... (Review)
Review
Castor oil is a vegetable product extracted from Ricinus communis L (castor seed), which is primarily considered an important commercial value for the manufacturing of soaps, lubricants, coatings, etc. It is rich in hydroxylated fatty acids (ricinoleic acid, 89-92%) and is widely used in the cosmetic, pharmaceutical, oleochemical, and agricultural industries. This oil has also been confirmed as a bactericidal, anti-inflammatory, and antiherpetic agents, due to the ricinoleic acid having functional groups, such as -COOH, -OH, and -C=C-. Furthermore, it is converted into various acid derivative compounds with several applications. Therefore, this article reviewed some reaction stages to the preparation of ricinoleic acid from castor oil. Several methods or reaction pathways were employed in the preparation procedure, such as the Twitchell and Colgate-Emery processes, as well as the alkaline catalyzed, transesterification with methyl ricinoleic, and lipase-catalyzed hydrolysis, respectively. Although each of these preparation methods has advantages and disadvantages, the most effective technique was the hydrolysis through the use of the enzyme lipozyme TL IM. Besides being a green method, the conversion rate in the hydrolysis process was 96.2 ± 1.5.
Topics: Ricinus communis; Castor Oil; Esterification; Fatty Acids; Ricinoleic Acids
PubMed: 35661063
DOI: 10.5650/jos.ess21226 -
Molecular Metabolism May 2023Emerging evidence suggest the existence of constant basal lipolysis and re-esterification of a substantial fraction of thus liberated fatty acids. In stimulated...
OBJECTIVE
Emerging evidence suggest the existence of constant basal lipolysis and re-esterification of a substantial fraction of thus liberated fatty acids. In stimulated lipolysis, the re-esterification is proposed to be a protective mechanism against lipotoxicity; however, the role of the lipolysis coupled to re-esterification under basal conditions has not been deciphered.
METHODS
We used adipocytes (in vitro differentiated brown and white adipocytes derived from a cell line or primary SVF culture) to study the effect of inhibition of re-esterification by pharmacological DGAT1 and DGAT2 inhibitors alone or in combination. We then evaluated cellular energetics, lipolysis flux, and lipidomic parameters along with mitochondrial properties and fuel utilization.
RESULTS
In adipocytes, DGAT1 and 2 mediated re-esterification is a moderator of fatty acid oxidation. Combined inhibition of both DGATs (D1+2i) increases oxygen consumption, which is largely due to enhanced mitochondrial respiration by lipolysis-derived fatty acids (FAs). Acute D1+2i selectively affects mitochondrial respiration without affecting the transcriptional homeostasis of genes relevant to mitochondrial health and lipid metabolism. D1+2i enhances the mitochondrial import of pyruvate and activates AMP Kinase to counteract CPT1 antagonism, thus facilitating the mitochondrial import of fatty acyl-CoA.
CONCLUSIONS
These data implicate the process of re-esterification in the regulation of mitochondrial FA usage and uncover a mechanism of FAO regulation via crosstalk with FA re-esterification.
Topics: Fatty Acids; Esterification; Lipid Metabolism; Lipolysis; Adipocytes, White
PubMed: 36878315
DOI: 10.1016/j.molmet.2023.101701 -
Journal of Lipid Research May 2017
Topics: Eicosanoids; Esterification; Humans; Phospholipids
PubMed: 28242788
DOI: 10.1194/jlr.C075986