Enzymatic Logic Gates with Noise-Reducing Sigmoid Response

Biochemical computing is an emerging field of unconventional computing that attempts to process information with biomolecules and biological objects using digital logic. In this work we survey filtering in general, in biochemical computing, and summarize the experimental realization of an and logic gate with sigmoid response in one of the inputs. The logic gate is realized with electrode-immobilized glucose-6-phosphate dehydrogenase enzyme that catalyzes a reaction corresponding to the Boolean and functions. A kinetic model is also developed and used to evaluate the extent to which the performance of the experimentally realized logic gate is close to optimal.

Bayesian L-optimal exact design of experiments for biological kinetic models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Kinetic properties of glycerophosphate oxidase isolated from dry baker's yeast

The glycerophosphate oxidase is a flavoprotein responsible for the catalysis of the oxidation of the glycerophosphate to dihydroxyacetone phosphate, through the reduction of the oxygen to hydrogen peroxide. The glycerophosphate oxidase from baker's yeast was specific for L-alpha-glycerol phosphate. It was estimated by monitoring the consumption of oxygen with an oxygraph. An increase of 32% in consumption of oxygen was obtained when the enzyme was concentrated 16-fold. The assay of enzyme was determined by the peroxidase chromogen method followed at 500 nm. The procedure for the standardization of the activity of the glycerophosphate oxidase from baker's yeast was accomplished, and the pH and temperature stability showed that the enzyme presented a high stability at pH 8.0, and the thermal stability was maintained up to 60 degrees C during I h. Such method allowed quantifying in the range 92-230 mM of glycerol phosphate, an important intermediate metabolite from lipid biosynthesis and glycolytic routes. (C) 2007 Elsevier B.V. All rights reserved.

A comparative study of protein and enzymatic activity in venoms of some common wasps (Hymenoptera: Vespidae) from São Paulo State

The Hymenoptera Aculeata venoms, with few exceptions, have been poorly studied and characterized. Nevertheless, they have raised increasing interest due to their medical importance, since accidents with these insects are fairly frequent in Brazil and may cause severe allergic reactions. The objectives of the present work were the quantitative characterization of the main allergenic enzymes present in the venom of the species Polybia paulista, Polybia ignobilis, Polistes simillimus, and Agelaia pallipes pallipes through biochemical assays for the determination of total protein content, as well as the level of the enzymatic activity of phospholipase, hyaluronidase, acid phosphatase and esterase. These results, in addition to providing biochemical knowledge about the venom of the species in question, also supply studies that allow phylogenetic inferences among them.

Antioxidant properties of brazilian tropical fruits by correlation between different assays

Four different assays (the Folin-Ciocalteu, DPPH, enzymatic method, and inhibitory activity on lipid peroxidation) based on radically different physicochemical principles and normally used to determine the antioxidant activity of food have been confronted and utilized to investigate the antioxidant activity of fruits originated from Brazil, with particular attention to more exotic and less-studied species (jurubeba, Solanum paniculatum; pequi, Caryocar brasiliense; pitaya, Hylocereus undatus; siriguela, Spondias purpurea; umbu, Spondias tuberosa) in order to (i) verify the correlations between results obtained by the different assays, with the final purpose to obtain more reliable results avoiding possible measuring-method linked mistakes and (ii) individuate the more active fruit species. As expected, the different methods give different responses, depending on the specific assay reaction. Anyhow all results indicate high antioxidant properties for siriguela and jurubeba and poor values for pitaya, umbu, and pequi. Considering that no marked difference of ascorbic acid content has been detected among the different fruits, experimental data suggest that antioxidant activities of the investigated Brazilian fruits are poorly correlated with this molecule, principally depending on their total polyphenolic content. © 2013 Elena Gregoris et al.

Kinetic role of a histidine residue in the T1 copper site of the laccase from Rigidoporus lignosus

Laccases (benzendiol:oxygen oxidoreductases; EC 1.10.3.2) catalyze the oxidation of a broad range of substrates, such as polyphenols, dyes and pollutants, and thus these enzymes are widely applied in industrial, biotechnological and environmental fields. In order to improve their biotechnological applications, a deep knowledge of structural factors involved in controlling their activity, in various experimental conditions and on different substrates, is required. In the present study, a laccase from the mushroom Rigidoporus lignosus was kinetically characterized. In particular, the stability, the effects of pH, ionic strength and fluoride ion concentration on the kinetic parameters were investigated, using three di-hydroxy-benzene isomers (1,2-dihydroxy-benzene, 1,3-dihydroxy-benzene and 1,4-dihydroxy-benzene) as substrates. The catalytic constant values of the laccase showed a bell-shaped pH profile, with the same optimum pH and pK(a) values for all tested substrates. This behavior appears to be due to the presence of an ionizable residue in the enzyme active site. To identify this residue, the enzyme was derivatized with diethylpyrocarbonate to modify accessible histidine residues, which, according to structural data, are present in the active site of this enzyme. The kinetic behavior of the derivatized laccase was compared with that of the native enzyme and the derivatized residues were identified by mass spectrometry. Mass spectrometry and kinetic results suggest the main role of His-457 in the control of the catalytic activity of laccase from R. lignosus. (C) 2013 Elsevier B.V. All rights reserved.

P-I class metalloproteinase from Bothrops moojeni venom is a post-proline cleaving peptidase with kininogenase activity: Insights into substrate selectivity and kinetic behavior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identification and enzymatic characterization of acid phosphatase from Burkholderia gladioli

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis of Structured Lipids by Enzymatic Interesterification of Milkfat and Soybean Oil in a Basket-Type Stirred Tank Reactor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Low Molecular Weight Sulfated Galactan Fragments From Botryocladia Occidentalis on the Pharmacological and Enzymatic Activity of Spla2 From Crotalus Durissus Cascavella

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Enzymatic and structural characterization of new PLA2 isoform isolated from white venom of Crotalus durissus ruruima

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Kinetic Analysis of Gill (Na+,K+)-ATPase Activity in Selected Ontogenetic Stages of the Amazon River Shrimp, (Decapoda, Palaemonidae): Interactions at ATP- and Cation-Binding Sites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of umbelliferone (7-hydroxycoumarin, 7-HOC) on the enzymatic, edematogenic and necrotic activities of secretory phospholipase A2 (sPLA2) isolated from Crotalus durissus collilineatus venom

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)