Navegando por Palavras-chave "Atividade enzimática"

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    Aumento da estabilidade da thimet-oligopeptidase (EC 3.24.15) imobilizada em nanopartículas de ouro (THOP- GNP)
    (Universidade Federal de São Paulo, 2023-04-14) Ramos, Marcos Paulo Cyrillo [UNIFESP]; Oliveira, Vitor [UNIFESP]; Icimoto, Marcelo Yudi [UNIFERSP]; http://lattes.cnpq.br/4421009566436244; http://lattes.cnpq.br/1476417303065197; https://lattes.cnpq.br/2390105077854601
    Objective: The development of biotechnological techniques that allow the use of proteases for disease treatment are an expanding field. However, the low stability of proteases is a limiting factor, and thus, an efficient strategy would be the immobilization of proteases such as THOP in gold nanoparticles (GNPs) for possible therapies. Methodology: The study protein was purified and characterized by chromatography and circular dichroism spectroscopy, thus demonstrating a pure protein (more than 90% purity) and with an adequate structure. Then, the synthesis of THOP-GNPs was carried out and their subsequent characterization by spectroscopy (UV-vis), proteolytic activity and atomic force microscopy. Results: The study protein was complexed with the nanoparticle and stability was observed, retaining 91.9% of its THOP-GNP activity synthesized with protein at 4 nM for 6h. The complexed enzyme resulted in retention of specificity by MALDI-TOF mass spectrometry, incubating the enzyme complexed to GNPs next to its natural substrate BK, maintaining the hydrolysis profile of its substrate, between the results of phenylalanine and serine, when it obtained the free enzyme. Conclusion: The results obtained from this work demonstrate that the characterization, synthesis and complexation of THOP in GNP can help us to standardize and apply this process with other biologically active proteins. When associated with GNPs, THOP presents high stability, potentially useful as an application in therapies when there is a need for BK processing.
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    Efeitos da ingestão de presas sobre o metabolismo energético e os níveis hormonais de cascavéis Crotalus durissus (Serpentes, Viperidae)
    (Universidade Federal de São Paulo, 2014-04-28) Oliveira, Fernando Bagnariolli de [UNIFESP]; Carvalho, José Eduardo de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Snakes that have foraging strategy such as ?sit-and-wait? and consequently feed on infrequent mode are excellent models to study the transition between the period of fasting and postprandial. The period of ingestion is accompanied by profound changes metabolism, thus an investigation of hormones related to metabolism and an analysis of the capacity of enzymatic pathways could elucidate questions about the processes that regulate this transition from fasting to feed. In this sense we analyze the concentration of thyroid hormones present in the plasma of rattlesnakes Crotalus durissus addition and leptin in plasma in fasted conditions and after ingestion of prey. In the same period we also analyzed the metabolic capabilities through measures of maximum activity of enzymes of glycogen synthesis (glycogen synthase - GS), an enzyme of the gluconeogenesis pathway (fructose 1,6 bisphosphatase - FBPase), enzymes of ? -oxidation lipid (? - hydroxyacyl -CoA dehydrogenase - HOAD), enzyme and metabolic pathway of ketone bodies (succinyl - CoA cetotransferase - SKT b - hydroxybutyrate dehydrogenase - HBDH) in tissue samples from liver, muscle, heart, kidney, stomach and intestine for fasted animals (45 and 90 days fasted) and after ingestion of the equivalent of 10 % of their body weight in mass of prey (24 hours, 48 hours and 120 hours). No different concentrations were found for the groups in the three hormones examined, T3, T4 e leptin. In the liver of rattlesnakes occurs regulation to form glycogen, analyzed by GS activity, in animals fed 48 hours after ingestion. Similar as result found in the kidney and muscle. With the exception of the heart, in all tissues there was a decrease in the ability to produce glucose from the gluconeogenesis, analyzed by FBPase in fasted animals for 90 days. In the heart there were also increased pathways of oxidation of lipids in fasted animals for 45 days, analyzed by HOAD, and increased metabolic pathway of ketone bodies in animals in 90 days fasting. These results suggest that although the hormones do not exert a regulatory role at least under the experimental conditions, the pathways analyzed by enzyme activities indicate possible points of regulations for times of fasting animals that foraging by ?sit-and-wait? strategies may face.