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1.
Enzyme Res ; 2014: 738739, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24818012

RESUMO

This study reports the immobilization of a new lipase isolated from oleaginous seeds of Pachira aquatica, using beads of calcium alginate (Alg) and poly(vinyl alcohol) (PVA). We evaluated the morphology, number of cycles of reuse, optimum temperature, and temperature stability of both immobilization methods compared to the free enzyme. The immobilized enzymes were more stable than the free enzyme, keeping 60% of the original activity after 4 h at 50°C. The immobilized lipase was reused several times, with activity decreasing to approximately 50% after 5 cycles. Both the free and immobilized enzymes were found to be optimally active between 30 and 40°C.

2.
Protein Pept Lett ; 13(1): 83-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16454675

RESUMO

The present work reports the characterization of Fastuosain, a novel cysteine protease of 25kDa, purified from the unripe fruits of Bromelia fastuosa, a wild South American Bromeliaceae. Proteolytic activity, measured using casein and synthetic substrates, was dependent on the presence of thiol reagents, having maximum activity at pH 7.0. The present work reports cDNA cloning of Fastuosain; cDNA was amplified by PCR using specific primers. The product was 1096pb long. Mature fastuosain has 217 residues, and with the proregion has a total length of 324 residues. Its primary sequence showed high homology with ananain(74%), stem bromelain (66%) and papain (44%).


Assuntos
Bromelia/enzimologia , Cisteína Endopeptidases/farmacologia , Sequência de Aminoácidos , Sequência de Bases , Cromatografia por Troca Iônica , Clonagem Molecular , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/isolamento & purificação , Primers do DNA , DNA Complementar , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos
3.
Eur J Biochem ; 271(21): 4270-4, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15511232

RESUMO

This paper reports the results obtained using the osmotic stress method applied to the purified cathodic and anodic hemoglobins (Hbs) from the catfish Hoplosternum littorale, a species that displays facultative accessorial air oxygenation. We demonstrate that water potential affects the oxygen affinity of H. littorale Hbs in the presence of an inert solute (sucrose). Oxygen affinity increases when water activity increases, indicating that water molecules stabilize the high-affinity state of the Hb. This effect is the same as that observed in tetrameric vertebrate Hbs. We show that both anodic and cathodic Hbs show conformational substrates similar to other vertebrate Hbs. For both Hbs, addition of anionic effectors, especially chloride, strongly increases the number of water molecules bound, although anodic Hb did not exhibit sensitivity to saturating levels of ATP. Accordingly, for both Hbs, we propose that the deoxy conformations coexist in at least two anion-dependent allosteric states, T(o) and T(x), as occurs for human Hb. We found a single phosphate binding site for the cathodic Hb.


Assuntos
Hemoglobinas/química , Fosfatos/química , Água/química , Trifosfato de Adenosina/química , Sítio Alostérico , Animais , Ânions , Sítios de Ligação , Peixes-Gato , Osmose , Oxigênio/química , Oxigênio/metabolismo , Ligação Proteica , Conformação Proteica , Estresse Fisiológico , Sacarose/química , Temperatura , Termodinâmica
4.
Protein Pept Lett ; 10(6): 551-9, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14683506

RESUMO

Crystal structure of hemoglobin isolated from the Brazilian maned wolf (Chrysocyon brachyurus) was determined using standard molecular replacement technique and refined using maximum-likelihood and simulated annealing protocols to 1.87A resolution. Structural and functional comparisons between hemoglobins from the Chrysocyon brachyurus and Homo sapiens are discussed, in order to provide further insights in the comparative biochemistry of vertebrate hemoglobins.


Assuntos
Hemoglobinas/química , Lobos , Animais , Brasil , Cristalização , Hemoglobinas/isolamento & purificação , Histidina , Ferro , Oxiemoglobinas/química , Conformação Proteica , Síncrotrons , Difração de Raios X
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