Search results for "Hydrolysis"

Self-assembled multivalent (SAMul) ligand systems with enhanced stability in the presence of human serum

2019

Self-assembled cationic micelles are an attractive platform for binding biologically-relevant polyanions such as heparin. This has potential applications in coagulation control, where a synthetic heparin rescue agent could be a useful replacement for protamine, which is in current clinical use. However, micelles can have low stability in human serum and unacceptable toxicity profiles. This paper reports the optimi- sation of self-assembled multivalent (SAMul) arrays of amphiphilic ligands to bind heparin in competitive conditions. Specifically, modification of the hydrophobic unit kinetically stabilises the self-assembled nanostructures, preventing loss of binding ability in the presence of…

2018

ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, al…

27Al NMR Study of the pH Dependent Hydrolysis Products of Al2(SO4)3 in Different Physiological Media

2018

Soluble inorganic aluminium compounds like aluminium sulfate or aluminium chloride have been challenged by the European Chemical Agency to induce germ cell mutagenicity. Before conducting mutagenicity tests, the hydrolysis products in water and in physiological solutions should be determined as a function of the concentration and pH. We used different 27Al NMR spectroscopic techniques (heteronuclear Overhauser effect spectroscopy (HOESY), exchange spectroscopy (EXSY), diffusion ordered (DOSY)) in this work to gain the information to study the aluminium species in solutions with Al2(SO4)3 concentrations of 50.0, 5.0, and 0.5 g/L and their pH and time dependent transformation. At low pH, thre…

LC-MS Analysis of Methylated RNA

2017

The detection and quantification of methylated RNA can be beneficial to understand certain cellular regulation processes such as transcriptional modulation of gene expression, immune response, or epigenetic alterations. Therefore, it is necessary to have methods available, which are extremely sensitive and accurate, for instance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we describe the preparation of RNA samples by enzymatic hydrolysis and the subsequent analysis of ribonucleosides by LC-MS/MS via NLS (Neutral loss scan) and DMRM (Dynamic multiple reaction monitoring). Also, we provide variations of these methods including chromatographic techniques and different kind…

Yeast trehalases: Two enzymes, one catalytic mission

2016

Abstract Background Trehalose is a non-reducing disaccharide highly conserved throughout evolution. In yeasts, trehalose hydrolysis is confined to the enzyme trehalase, an α-glucosidase specific for trehalose as sole substrate. Two kinds of trehalase activity exist in yeasts: neutral and acid enzymes. Scope of the review This review makes a comparative survey of the main biochemical and genetic parameters, regulatory systems, tridimensional structure and catalytic mechanism of the two yeast trehalases. Major conclusions The yeast neutral and acid trehalases display sharp differences in biochemical features (optimum pH, Mr or amino acid sequence) physiological roles, subcellular location (cy…

GH57 amylopullulanase from Desulfurococcus amylolyticus JCM 9188 can make highly branched cyclodextrin via its transglycosylation activity.

2018

Abstract Desulfurococcus amylolyticus is an anaerobic and hyperthermophilic crenarchaeon that can use various carbohydrates as energy sources. We found a gene encoding a glycoside hydrolase family 57 amylolytic enzymes (DApu) in a putative carbohydrate utilization gene cluster in the genome of D. amylolyticus . This gene has an open reading frame of 1,878 bp and consists of 626 amino acids with a molecular mass of 71 kDa. Recombinant DApu (rDApu) completely hydrolyzed pullulan to maltotriose by attacking α-1,6-glycosidic linkages, and was able to produce glucose and maltose from soluble starch and amylopectin. Although rDApu showed no activity toward α-cyclodextrin (CD) and β-CD, maltooctao…

Development of enzymatically-active bacterial cellulose membranes through stable immobilization of an engineered beta-galactosidase

2018

Enzymatically-active bacterial cellulose (BC) was prepared by non-covalent immobilization of a hybrid enzyme composed by a β-galactosidase from Thermotoga maritima (TmLac) and a carbohydrate binding module (CBM2) from Pyrococcus furiosus. TmLac-CBM2 protein was bound to BC, with higher affinity at pH 6.5 than at pH 8.5 and with high specificity compared to the non-engineered enzyme. Both hydrated (HBC) and freeze-dried (DBC) bacterial cellulose showed equivalent enzyme binding efficiencies. Initial reaction rate of HBC-bound enzyme was higher than DBC-bound and both of them were lower than the free enzyme. However, enzyme performance was similar in all three cases for the hydrolysis of 5% l…

Bovine plasma hydrolysates' iron chelating capacity and its potentiating effect on ferritin synthesis in Caco-2 cells.

2020

The low bioavailability of iron is one factor that contributes to its deficiency in the human diet. For this reason, it is necessary to find compounds that can form iron chelates so that these can be added to foods that contain iron to improve its bioavailability at the intracellular level. In this study, we assessed the relationship between bovine plasma hydrolysates' iron chelating ability and their degree of hydrolysis. The hydrolysate with the highest chelating capacity was fractionated and each fraction's chelating capacity was subsequently assessed. Each fraction's effect on ferritin synthesis in Caco-2 cells was also determined. The results showed that bovine plasma hydrolysates with…

7,8-hydroxy-2′-deoxyguanosine/2′-deoxiguanosine ratio determined in hydrolysates of brain DNA by ultrachromatrography coupled to tandem mass spectrom…

2017

7,8-hydroxy-2'-deoxyguanosine (8-OHdG) is an abundant DNA lesion formed by oxidation of the nucleoside 2'-deoxyguanosine (2-dG) and one of the most studied and accepted oxidative stress biomarkers. 8-OHdG has a strong carcinogenic potential, and prolonged oxidative stress heightens pathological conditions and especially cancer risk. Our aim was to develop, validate and apply a reliable method to assess DNA oxidation in genomic cellular DNA of sensible target organs such as brain. A procedure to isolate and digest the DNA of brain tissue properly for further detection of 8-OHdG and 2-dG by Ultra Performance Liquid Chromatography tandem Mass Spectrometry (UPLC-MS/MS) was optimized. The UPLC-M…

Overactivation of the endocannabinoid system alters the antilipolytic action of insulin in mouse adipose tissue.

2017

Evidence has accumulated that obesity-related metabolic dysregulation is associated with overactivation of the endocannabinoid system (ECS), which involves cannabinoid receptor 1 (CB1R), in peripheral tissues, including adipose tissue (AT). The functional consequences of CB1R activation on AT metabolism remain unclear. Since excess fat mobilization is considered an important primary event contributing to the onset of insulin resistance, we combined in vivo and in vitro experiments to investigate whether activation of ECS could alter the lipolytic rate. For this purpose, the appearance of plasma glycerol was measured in wild-type and CB1R−/− mice after acute anandamide administration or inh…