In silico analysis identifies a C3HC4-RING finger domain of a putative E3 ubiquitin-protein ligase located at the C-terminus of a polyglutamine-containing protein

Almost identical polyglutamine-containing proteins with unknown structures have been found in human, mouse and rat genomes (GenBank AJ277365, AF525300, AY879229). We infer that an identical new gene (RING) finger domain of real interest is located in each C-terminal segment. A three-dimensional (3-D) model was generated by remote homology modeling and the functional implications are discussed. The model consists of 65 residues from terminal position 707 to 772 of the human protein with a total length of 796 residues. The 3-D model predicts a ubiquitin-protein ligase (E3) as a binding site for ubiquitin-conjugating enzyme (E2). Both enzymes are part of the ubiquitin pathway to label unwanted proteins for subsequent enzymatic degradation. The molecular contact specificities are suggested for both the substrate recognition and the residues at the possible E2-binding surface. The predicted structure, of a ubiquitin-protein ligase (E3, enzyme class number 6.3.2.19, CATH code 3.30.40.10.4) may contribute to explain the process of ubiquitination. The 3-D model supports the idea of a C3HC4-RING finger with a partially new pattern. The putative E2-binding site is formed by a shallow hydrophobic groove on the surface adjacent to the helix and one zinc finger (L722, C739, P740, P741, R744). Solvent-exposed hydrophobic amino acids lie around both zinc fingers (I717, L722, F738, or P765, L766, V767, V733, P734). The 3-D structure was deposited in the protein databank theoretical model repository (2B9G, RCSB Protein Data Bank, NJ).

Perfil sensorial e aceitação de bebida láctea achocolatada

O perfil sensorial de bebida láctea achocolatada foi obtido por meio da Análise Descritiva Quantitativa (ADQ), utilizando três marcas comerciais do produto. Doze termos descritivos foram desenvolvidos por uma equipe de provadores selecionados e treinados, que geraram também a definição de cada termo e as amostras referência. Os resultados foram submetidos à ANOVA, teste de Tukey e Análise de Componentes Principais. A bebida láctea achocolatada da marca A caracterizou-se por apresentar maior intensidade de doçura, aroma e sabor de caramelo, enquanto as características predominantes da marca B foram a cor marrom, viscosidade e arenosidade muito intensos. O produto da marca C diferiu dos demais por apresentar maior aroma e sabor de leite. Foi também realizado um teste de aceitação para avaliar as amostras de uma forma global, quanto a intensidade do ideal de doçura e a intenção de compra. Todas as marcas apresentaram boa aceitabilidade global, não apresentando diferença significativa entre si, assim como a intenção de compra. O teste com o consumidor indicou que a amostra B apresentou intensidade de doçura ideal.

Design of automatic control system for the precipitation of bromelain from the extract of pineapple wastes

In this work, bromelain was recovered from ground pineapple stem and rind by means of precipitation with alcohol at low temperature. Bromelain is the name of a group of powerful protein-digesting, or proteolytic, enzymes that are particularly useful for reducing muscle and tissue inflammation and as a digestive aid. Temperature control is crucial to avoid irreversible protein denaturation and consequently to improve the quality of the enzyme recovered. The process was carried out alternatively in two fed-batch pilot tanks: a glass tank and a stainless steel tank. Aliquots containing 100 mL of pineapple aqueous extract were fed into the tank. Inside the jacketed tank, the protein was exposed to unsteady operating conditions during the addition of the precipitating agent (ethanol 99.5%) because the dilution ratio "aqueous extract to ethanol" and heat transfer area changed. The coolant flow rate was manipulated through a variable speed pump. Fine tuned conventional and adaptive PID controllers were on-line implemented using a fieldbus digital control system. The processing performance efficiency was enhanced and so was the quality (enzyme activity) of the product.

Uma avaliação das contribuições de Stiglitz à teoria dos mercados financeiros

The objective and originality of this paper lie in identifying Stiglitz's main theoretical contributions to Financial Economics and in briefly portraying the contemporary economic thought out of which these contributions emerged as well as in suggesting their connections with the subsequent economic thought. Grounded on a detailed analysis of Stiglitz's works on finance, his most important theoretical findings are singled out and gathered into four issues: (1) the conditions under which the Modigliani-Miller theorem is valid; (2) the inconsistency inherent to the efficient market hypothesis; (3) the microeconomic effects of asymmetrical information in financial markets; and (4) its real macroeconomic effects. In all of these topics, the focal point of Stiglitz's theoretical research is the unrealistic underpinnings on which the Arrow-Debreu competitive equilibrium model relies. It is also emphasised that this same perspective he coherently followed to construct a fully-fledged theoretical framework would be preserved in his empirical investigations, notably about developing countries, on which he has concentrated effort since the beginnings of the nineties.