RESUMO
The feasibility of using saponification coupled to extraction with mixed micellar systems to recover bioactive compounds from soybean oil deodorizer distillate, was evaluated for the first time. Under the selected conditions, saponification with KOH 0.6 M and aqueous micellar system prepared with Tergitol 15-S-7 9% w/w, rhamnolipids 0.25 %w/w and sodium citrate 100 mM pH 5.00, at 65 °C, allow the recovery of almost 100% of α- and δ- tocopherols, and 90% of γ-tocopherols. LC-MS measurements demonstrated that the final extract also contained phytosterols and squalene. Additionally, the obtained extract preserved about 100% of the total antioxidant activity. This result was attributable to the fact that 93% of the tocopherols recovered in the micellar phases resulted to be associated with surfactant micelles, environment that is known to improve their antioxidant capacity. These results open perspectives to the use of this methodology to extract these valuable compounds from complex oily sources.
Assuntos
Fitosteróis , Óleo de Soja , Cromatografia Líquida , Micelas , Fitosteróis/química , Óleo de Soja/química , Tocoferóis/análiseRESUMO
Ethoxylated aliphatic surfactants belonging to the Genapol and Tergitol series were assessed as extraction systems of isoflavones. They showed good extraction properties when compared with different solvents, the Genapol X-080 exhibiting the best performance. Available commercial isoflavone pills were used, as a starting simple matrix, to determine the parameters that affect the extraction procedure. The temperature and the surfactant concentration showed to be factors that favored significantly the extraction performance. The application of optimized variables (Genapol X-080 11%â¯m/m, pH 4.5; extraction temperature of 54⯰C and extraction time of 60â¯min) on soybean flour (natural) allowed extracting 3.237⯱â¯0.173â¯mg of isoflavone per gram of treated flour. This result was three times what it was for methanol under identical conditions. Extraction with these micellar systems represents a sustainable alternative methodology for industrial purposes due to its low cost, biodegradability, non-toxicity and easy scaling up.
Assuntos
Fracionamento Químico/métodos , Glycine max/química , Isoflavonas/isolamento & purificação , Polietilenoglicóis/química , Tensoativos/química , Álcoois Graxos/química , Farinha , Concentração de Íons de Hidrogênio , Micelas , Solventes/química , TemperaturaRESUMO
The emergence of old and new antibiotic resistance created in the last decades revealed a substantial medical need for new classes of antimicrobial agents. The antimicrobial activity of sulfa drugs is often enhanced by complexation with metal ions, which is in concordance with the well-known importance of metal ions in biological systems. Besides, sulfonamides and its derivatives constitute an important class of drugs, with several types of pharmacological agents possessing antibacterial, anti-carbonic anhydrase, diuretic, hypoglycemic, antithyroid, antiviral and anticancer activities, among others. The purpose of this work has been the obtainment, characterization and determination of biological properties (antibacterial, antifungal, mutagenicity and phytotoxicity) of a new Co(III)-sulfathiazole complex: Costz, besides of its interaction with bovine serum albumin (BSA). The reaction between sodium sulfathiazole (Nastz) and cobalt(II) chloride in the presence of H2O2 leads to a brown solid, [CoIII(stz)2OH(H2O)3], (Costz). The structure of this compound has been examined by means of elemental analyses, FT-IR, 1H NMR, UV-Visible spectrometric methods and thermal studies. The Co(III) ion, which exhibits a distorted octahedral environment, could coordinate with the N thiazolic atom of sulfathiazolate. The complex quenched partially the native fluorescence of bovine serum albumin (BSA), suggesting a specific interaction with the protein. The Costz complex showed, in vitro, a moderate antifungal activity against Aspergillus fumigatus and A. flavus. As antibacterial, Costz displayed, in vitro, enhanced activity respective to the ligand against Pseudomonas aeruginosa. Costz did not show mutagenic properties with the Ames test. In the Allium cepa test the complex showed cytotoxic properties but not genotoxic ones. These results may be auspicious, however, further biological studies are needed to consider the complex Costz as a possible drug in the future.
Assuntos
Cobalto/química , Complexos de Coordenação/síntese química , Sulfatiazóis/química , Allium/efeitos dos fármacos , Allium/crescimento & desenvolvimento , Animais , Antibacterianos/síntese química , Antibacterianos/farmacologia , Antifúngicos/síntese química , Antifúngicos/farmacologia , Aspergillus flavus/efeitos dos fármacos , Aspergillus fumigatus/efeitos dos fármacos , Bovinos , Complexos de Coordenação/metabolismo , Complexos de Coordenação/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Peróxido de Hidrogênio/química , Testes de Sensibilidade Microbiana , Testes de Mutagenicidade , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Ligação Proteica , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , SulfatiazolRESUMO
Enzymatic hydrolysis of soybean meal protein isolate (SPI) obtained under two temperature conditions with Corolase PP was studied, assessing the impact of hydrolysis on potential antioxidant and antihypertensive activities. The protein was isolated from soybean meal under controlled conditions of time and temperature (70 °C, 1h; 90 °C, 30 min). Degree of hydrolysis assessed the progress of hydrolysis at different sampling times. For hydrolysates the antioxidant and angiotensin-converting-enzyme (ACE) inhibitory activities were measured. As observed, the DH was increasing until reaching 20% at 10h with disappearance of globular proteins and generation of low molecular weight peptides (less than 3kDa). A significant increase in antioxidant and ACE inhibitory capacities was observed. Five main peptides were identified, which may explain through their sequences the bioactive properties analyzed. Through this study was possible to obtain for the first time with Corolase PP soy hydrolysates with potential antioxidant and ACE inhibitory activities, which can be used to obtain new added value functional ingredients from soy meal.
Assuntos
Peptídeos/química , Proteínas de Soja/análise , Argentina , Farinha , HidróliseRESUMO
Phospholipase A2 (PLA2) and protease (P) are enzymes responsible of myotoxic, edematogenic and hemostasis disorder effects observed in the envenomation by Bothrops alternatus pitviper. Their partitioning coefficient (Kp) in different polyethyleneglycol/potassium phosphate aqueous two-phase systems (ATPSs) was determined in order to both achieve a better understanding of the partitioning mechanism and define optimal conditions for toxin isolation. Polyethyleneglycols (PEGs) of molecular weights 1000; 3350; 6000 and 8000; different temperatures (5, 20 and 37 °C) and phase volume ratios of 0.5; 1 and 2 were assayed. PLA2 partitioned preferentially to the top phase while P mainly distributed to the bottom phase. Either entropically- or enthalpically-driven mechanisms were involved in each case (PLA2 and P). The aqueous two-phase system formed by PEG of MW 3350 (12.20% wt/wt) and KPi pH 7.0 (11.82% wt/wt) with a volume ratio of one and a load of 1.25 mg of venom/g of system showed to be the most efficient to recover both enzymes. It allowed obtaining the 72% of PLA2 in the top phase with a purification factor of 2 and the 82% of P at the bottom phase simultaneously. A further adsorption batch step with DEAE-cellulose was used to remove satisfactorily the PEG from the top phase and recover the active PLA2. The proposed methodology is simple, inexpensive, and only requires professionals trained in handling basic laboratory equipment. It could be easily adoptable by developing countries in which the snakebite accidents cause considerable morbidity and mortality.
Assuntos
Bothrops , Venenos de Crotalídeos/química , Fosfolipases A2 , Serina Endopeptidases , Animais , DEAE-Celulose , Fosfolipases A2/química , Fosfolipases A2/isolamento & purificação , Polietilenoglicóis/química , Serina Endopeptidases/química , Serina Endopeptidases/isolamento & purificaçãoRESUMO
Enzyme extraction using aqueous two-phase systems (ATPS) has been increasingly used as a primary recovery technique which integrates the clarification, concentration and partial purification of important biomolecules from their natural source in a single step. The goal of this work was to optimize the extraction of trypsin from pancreas homogenate with polyethylene glycol and sodium citrate (PEG/NaCit) ATPS by using the tools of experimental design. The variables NaCl concentration - added inert salt -, the top/bottom phase volume ratio - Vr - and the biomass loaded into the system - in percentage - were selected as the main factors in the trypsin extraction. The yield (%) and the purification factor of trypsin were considered the responses to be optimized. The central composite design and the response surface analysis proved to be suitable tools for a quick and efficient study. As a result, the optimal extraction conditions in PEG3350/NaCit system were 3.34% wt/wt for NaCl concentration, a biomass load which represented 9.30% wt/wt of the total ATPS mass and 6.37 top/bottom volume ratio giving a purification factor of 2.55 and a yield of 99.7% in top phase.
Assuntos
Bioquímica/métodos , Citratos/química , Pâncreas/enzimologia , Polietilenoglicóis/química , Tripsina/isolamento & purificação , Animais , Bovinos , Concentração de Íons de Hidrogênio , Extratos Pancreáticos/metabolismo , Análise de Regressão , Reprodutibilidade dos Testes , Citrato de Sódio , ÁguaRESUMO
The effect of Triton X-114 on the physicochemical properties of a single-chain antibody fragment (scFv) has been studied. According to the far UV circular dichroism spectroscopy, the secondary structure of the recombinant antibody was not significantly affected by the presence of Triton. From the antibody tertiary structure analysis, it was found that the surfactant could be located around the tryptophan molecules accessible to the solvent, diminishing the polarity of its environment but maintaining most of the protein structure integrity. However, in certain conditions of high temperature and high concentration of denaturant molecules, the presence of TX could compromise the antibody fragment stability. These results represent a previous step in designing scFv purification protocols and should be considered prior to developing scFv liquid-liquid extraction procedures.
Assuntos
Fragmentos de Imunoglobulinas/química , Região Variável de Imunoglobulina/química , Polietilenoglicóis/farmacologia , Proteínas Recombinantes/química , Dicroísmo Circular , Fragmentos de Imunoglobulinas/imunologia , Fragmentos de Imunoglobulinas/isolamento & purificação , Extração Líquido-Líquido , Octoxinol , Polietilenoglicóis/química , Estabilidade Proteica , Estrutura Secundária de Proteína , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , TensoativosRESUMO
Cellular nucleic acid binding protein (CNBP) is a highly conserved multi-zinc knuckle protein that enhances c-MYC expression, is related to certain human muscular diseases and is required for proper rostral head development. CNBP binds to single-stranded DNA (ssDNA) and RNA and acts as nucleic acid chaperone. Despite the advances made concerning CNBP biological roles, a full knowledge about the structure-function relationship has not yet been achieved, likely due to difficulty in obtaining pure and tag-free CNBP. Here, we report a fast, simple, reproducible, and high-performance expression and purification protocol that provides recombinant tag-free CNBP from Escherichia coli cultures. We determined that tag-free CNBP binds its molecular targets with higher affinity than tagged-CNBP. Furthermore, fluorescence spectroscopy revealed the presence of a unique and conserved tryptophan, which is exposed to the solvent and involved, directly or indirectly, in nucleic acid binding. Size-exclusion HPLC revealed that CNBP forms homodimers independently of nucleic acid binding and coexist with monomers as non-interconvertible forms or in slow equilibrium. Circular dichroism spectroscopy showed that CNBP has a secondary structure dominated by random-coil and ß-sheet coincident with the sequence-predicted repetitive zinc knuckles motifs, which folding is required for CNBP structural stability and biochemical activity. CNBP structural stability increased in the presence of single-stranded nucleic acid targets similar to other unstructured nucleic acid chaperones. Altogether, data suggest that CNBP is a flexible protein with interspersed structured zinc knuckles, and acquires a more rigid structure upon nucleic acid binding.
RESUMO
The partitioning patterns of papain (PAP) and bromelain (BR), two well-known cysteine-proteases, in polyethyleneglycol/sodium citrate aqueous two-phase systems (ATPSs) were determined. Polyethyleneglycols of different molecular weight (600, 1000, 2000, 4600 and 8000) were assayed. Thermodynamic characterization of partitioning process, spectroscopy measurements and computational calculations of protein surface properties were also carried out in order to explain their differential partitioning behavior. PAP was observed to be displaced to the salt-enriched phase in all the assayed systems with partition coefficients (KpPAP) values between 0.2 and 0.9, while BR exhibited a high affinity for the polymer phase in systems formed by PEGs of low molecular weight (600 and 1000) with partition coefficients (KpBR) values close to 3. KpBR values resulted higher than KpPAP in all the cases. This difference could be assigned neither to the charge nor to the size of the partitioned biomolecules since PAP and BR possess similar molecular weight (23,000) and isoelectric point (9.60). The presence of highly exposed tryptophans and positively charged residues (Lys, Arg and His) in BR molecule would be responsible for a charge transfer interaction between PEG and the protein and, therefore, the uneven distribution of BR in these systems.
Assuntos
Bromelaínas/química , Extração Líquido-Líquido , Papaína/química , Bromelaínas/metabolismo , Dicroísmo Circular , Ativação Enzimática , Papaína/metabolismo , Polietilenoglicóis/química , TermodinâmicaRESUMO
Affinity partitioning combines the partitioning behavior of biological macromolecules in aqueous two-phase systems with the principle of biorecognition. Among the numerous substances that have been evaluated as ligands, the reactive dyes constitute a group of low cost textile dyes which have proved to act as biomimetic ligands for many enzymes. The ability of reactive yellow 2 (RY2) to interact with trypsin (TRP) and chymotrypsin (ChTRP) and its behavior in aqueous two-phase systems formed by polyethylene glycol (PEG) and sodium citrate (NaCit) - were investigated. Different variables such as PEG molecular weight, tie line length and dye concentration were analyzed. RY2 showed to bind specifically to both TRP and ChTRP with affinity constants near to 10(3)M(-1). Its partition equilibrium is practically displaced to the top phase in systems formed by PEG of different molecular weight. Addition of this dye to PEG 8000/NaCit systems until a final concentration of 0.196% (w/w) induced an increase in TRP and ChTRP partition coefficients of at least 2 times over that in the absence of the ligand. These findings demonstrate that RY2 fulfils all the requirements to be considered as an affinity ligand in aqueous two-phase partitioning of TRP and ChTRP.