Produção, purificação, clonagem e aplicação de enzimas líticas

Lytic enzymes such as beta-1,3 glucanases, proteases and chitinases are able to hydrolyse, respectively, beta-1,3 glucans, mannoproteins and chitin, as well as the cell walls of many yeast species. Lytic enzymes are useful in a great variety of applications including the preparation of protoplasts; the extraction of proteins, enzymes, pigments and functional carbohydrates; pre-treatment for the mechanical rupture of cells; degradation of residual yeast cell mass for the preparation of animal feed; analysis of the yeast cell wall structure and composition; study of the yeast cell wall synthesis and the control of pathogenic fungi. This review presents the most important aspects with respect to lytic enzymes, especially their production, purification, cloning and application.

Inibidores da HIV-integrase: potencial abordagem farmacológica para tratamento da AIDS

AIDS has the HIV as its etiological agent. Researches has been done to find new pharmacological agents to be used in therapy, because of problems of resistance and side effects. The HIV-integrase inhibitors are some of those new agents that are being studied. This updating focusses on the fundamental information about HIV and HIV-integrase and the main methods being used to develop these new drugs, with examples for each case.

Enzimas termoestáveis: fontes, produção e aplicação industrial

REVIEW: Living organisms encountered in hostile environments that are characterized by extreme temperatures rely on novel molecular mechanisms to enhance the thermal stability of their proteins, nucleic acids, lipids and cell membranes. Proteins isolated from thermophilic organisms usually exhibit higher intrinsic thermal stabilities than their counterparts isolated from mesophilic organisms. Although the molecular basis of protein thermostability is only partially understood, structural studies have suggested that the factors that may contribute to enhance protein thermostability mainly include hydrophobic packing, enhanced secondary structure propensity, helix dipole stabilization, absence of residues sensitive to oxidation or deamination, and increased electrostatic interactions. Thermostable enzymes such as amylases, xylanases and pectinases isolated from thermophilic organisms are potentially of interest in the optimization of industrial processes due to their enhanced stability. In the present review, an attempt is made to delineate the structural factors that increase enzyme thermostability and to document the research results in the production of these enzymes.

Síntese, avaliação biológica e modelagem molecular de arilfuranos como inibidores da enzima tripanotiona redutase

Trypanosoma cruzi is a protozoan parasite that causes a severe disease (Chagas'disease) in Central and South America. The currently available chemotherapeutic agents against this disease are still inadequate. The enzyme trypanothione reductase (TR) is considered a validated molecular target for the development of new drugs against this parasite. In this regard, a series of arylfurans based on 2,5-bis-(4-acetamidophenyl)furan was synthesized and tested for their in vitro inhibitory activity against TR. Molecular modeling studies of putative enzyme-inhibitor complexes revealed a possible mechanism of interaction. From synthesized compounds, a benzylaminofuran derivative was found to be more active than the lead compound.

Glutationa e enzimas relacionadas: papel biológico e importância em processos patológicos

Glutathione (GSH) and related enzymes are pivotal for the normal functioning of several important biological processes. In this review we discuss the biosynthesis and the catalytic cycles of glutathione as well as the major GSH-related enzymes. We also present how glutathione and enzymes are involved in cancer and the chromatographic and non-chromatographic methods used to analyze glutathione and/or its derivatives.

Síntese e modificações de derivados heterocíclicos de D-arabinose: potenciais inibidores de glicose-6-fosfato isomerase e de glicosamina-6-fosfato sintase

The synthesis of -5-(D-arabino-1,2,3,4-tetrahydroxybutyl)tetrazole and -2-(D-arabino-1,2,3,4-tetra-acetoxybutyl)-5-methyl-1,3,4-oxadiazole from D-arabinose is described. Attempts at removing the protecting groups of the oxadiazole derivative were unsuccessful, leading to products resulting from the opening of the oxadiazole ring. The unprotected tetrazole derivative was selectively phosphorylated at the primary hydroxyl group with diethylphosphoryl chloride. The resulting 5-[D-arabino-4-(diethylphosphoryloxy)-1,2,3-trihydroxybutyl]tetrazole is a protected form of a potential inhibitor of the enzymes glucose-6-phosphate isomerase and glucosamine synthase.

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas

The development and characterization of bioreactors or IMER (immobilized enzyme reactors) as research tools are important in the scope of medicinal chemistry and constitute an alternative for the rational development of drugs. This approach does not require highly purified enzymes or a great amount of protein, but increase the enzymatic stability against heat, organic solvents and pH, without too much loss of catalyst activity. Immobilized enzyme reactors (IMER) can be used for the accomplishment of high efficiency screening on-line and, thus inhibitors can be quickly identified. Here, we emphasize the development of IMER by use of different methods of immobilization and chromatographic supports. Their applications, in different areas of research, are also fully discussed.

Proteínas quinases: características estruturais e inibidores químicos

Protein kinases are one of the largest protein families and they are responsible for regulation of a great number of signal transduction pathways in cells, through the phosphorylation of serine, threonine, or tyrosine residues. Deregulation of these enzymes is associated with several diseases including cancer, diabetes and inflammation. For this reason, specific inhibition of tyrosine or serine/threonine kinases may represent an interesting therapeutic approach. The most important types of protein kinases, their structural features and chemical inhibitors are discussed in this paper. Emphasis is given to the small-molecule drugs that target the ATP-binding sites of these enzymes.

Influência da ação das enzimas alcalase e flavourzyme no grau de hidrólise das proteínas de carne de frango

To study the action of Alcalase and Flavourzyme on the proteins of chicken meat, the influence of the substrate concentration [S], enzyme concentration [E] and hydrolysis time on the degree of hydrolysis (DH) of the proteins was evaluated. The highest DH for breast meat was obtained with a [S] of 3.3% (w/v), with a [E] of 6% (w/w) and reaction time of 90 min, for both enzymes. For thigh meat the conditions to get the highest DH were: [S] of 5% (w/v), [E] of 8% (w/w) and a reaction time of 120 min, for both enzymes.

Estudos de QSAR 3D para um conjunto de inibidores de butirilcolinesterase humana

Alzheimer's disease (AD) is considered the main cause of cognitive decline in adults. The available therapies for AD treatment seek to maintain the activity of cholinergic system through the inhibition of the enzyme acetylcholinesterase. However, butyrylcholinesterase (BuChE) can be considered an alternative target for AD treatment. Aiming at developing new BuChE inhibitors, robust QSAR 3D models with high predictive power were developed. The best model presents a good fit (r²=0.82, q²=0.76, with two PCs) and high predictive power (r²predict=0.88). Analysis of regression vector shows that steric properties have considerable importance to the inhibition of the BuChE.

Avaliação do uso de inibidores de etileno sobre a produção de compostos voláteis e de mangiferina em manga

Effects of two ethylene inhibitors, 1-methylcylopropene (1-MCP) and aminoethoxyvinylglycine (AVG), on production of volatile compounds and mangiferin (a bioactive xanthone) in 'Tommy Atkins' mango fruit were investigated. Volatile composition and mangiferin content, in treated and untreated fruits at three maturity, stages were determined by SPME-GC-MS and HPLC, respectively. These chromatographical analysis revealed that the volatile profiles and mangiferin concentrations were not significantly different, suggesting that the use of ethylene inhibitors does not affect the mango aroma and functional properties relative to this xanthone. Moreover, a simple, precise and accurate HPLC method was developed for quantifying mangiferin in mango pulp.

Aplicação de quitosana como suporte para a imobilização de enzimas de interesse industrial

Chitosan, poly[β-(1-4)-linked-2-amino-2-deoxy-D-glucose], is the N-deacetylated product of chitin which is a major component of arthropod and crustacean shells such as lobsters, crabs, shrimps, and cuttlefishes. In addition, chitosan has many significant biological and chemical properties such as biodegradability, biocompatibility and bioactivity as well as polycationic properties. Thus, it has been widely used in many industrial and biomedical applications including wastewater treatment, chromatographic support, carriers for controlled drug delivery and enzyme immobilization. This review is an insight into the exploitation of utilization of chitosan based-supports in different geometrical configurations on the immobilization of enzymes by different protocols for further application in biotransformation reactions.

Ácido myrsinoico a e derivado: inibidores da fotossíntese in vitro

Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methylviologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P680 and Q A. Chlorophyll a fluorescence measurements confirmed the behavior of the compounds (pool of quinones).

Avaliação de furanocumarinas como inibidores da fotossíntese através de ensaios de fluorescência da clorofila a

The evaluations of Chorophyll a fluorescence emitted by superior plants carry structural information and photosynthetic apparatus function. Quantitative analysis apparatus of fluorescence kinetic were measured by energy flows (ABS), (TR), (ET) and (DI), known as phenomenological phenomena of OJIP test. Four furocoumarins were isolated from Ruta graveolens (Rutaceae), and chorophyll a (Chl a) fluorescence assays were performed with these compounds to evaluate the photosynthesis inhibition potential. This test was realized in spinach`s leaf discs and in Lolium perenne leaves. The results indicated the herbicide potential mainly for bergapten and chalepin.

Inmovilización de enzimas lignocelulolíticas en nanopartículas magnéticas

Due to the need for more efficient, economical and environmentally-friendly technological processes, the use of enzymes has increased. However, reuse of enzymatic hydrolytic complex is required. The immobilization of enzymes provides a basis for stability and allows their reuse reflected in aspects of economic feasibility. Magnetic nanoparticles are a promising supports since their magnetic character allows retrieval by applying an external magnetic field. This article presents an analysis and discussion of methods of biocatalyst immobilization, emphasizing lignocellulolytic enzymes immobilized in magnetic nanoparticles and their applications for the production of high-value compounds such as bioethanol.