1,721,064 research outputs found
Purification and Characterization of Soluble Cichorium intybus Var. silvestre Lipoxygenase
No full textA water-soluble lipoxygenase enzyme (EC 1.13.11.12; LOX) occurring in the red cultivar produced
in the geographical area of Chioggia (Italy) of Cichorium intybus var. silvestre was isolated and
characterized. The molecular mass of the enzyme was estimated to be 74000 Da by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography. The isoelectric point
was pH 6.85. The optimum values of pH, ionic strength, and temperature, shown by isoresponse
surface calculated by a randomized multilevel factorial design, were 7.58, 30 mM, and 38.5 °C,
respectively. The enzyme showed high specificity toward linoleic acid, and the study of the variation
of linoleic acid concentration between 30 and 300 íM, in the presence of Tween 20 at a concentration
lower than the critical micelle concentration (0.01 v/v), resulted in a typical Michaelis-Mentem curve
with KM and Vmax values of 1.49 10-4 M and 2.049 íM min-1 mg-1, respectively. The biochemical
properties, the kinetic parameters found, and the carotene-bleaching activity shown in aerobic
conditions seem to indicate that the isolated enzyme is a lipoxygenase type III according to the
indications given for soybean isoenzymes
Dynamic of beta(2)-microglobulin fibril formation and reabsorption: the role of proteolysis.
No full textDialysis-related amyloidosis (DRA) is caused by the deposition, in target tissues, of beta(2)-microglobulin (beta(2)M) in fibrillar conformation. Several reports indicate that fibrillar beta(2)M is chemically heterogeneous and such heterogeneity is partially related to the presence of truncated species of the protein. In association with the full-length species, a beta(2)M isoform lacking six N-terminal residues is present in all the samples of our collection of ex vivo fibrils. The pattern of proteolytic cleavage in amyloidosis and in other diseases is completely different, as demonstrated by the absence in fibrillar beta(2)M of the cleavage at lysine 58, which is contrary to that described in rheumatoid arthritis and other diseases. The role of limited proteolysis of beta(2)M in the pathogenesis of the disease is uncertain. However, we have shown that the apparently minor modification of the intact protein, such as the removal of N-terminal hexapeptide, is capable of dramatically affecting its stability, protection from proteolytic digestion, and enhance its capacity to make in vitro amyloid fibrils. The structure, folding dynamic, and function of the truncated species of beta(2)M, peculiar of DRA, could shed new light on the mechanism of beta(2)M fibril formation and reabsorption
Limited proteolysis in the investigation of beta2-microglobulin amyloidogenic and fibrillar states
No full text
Search of ligands for the amyloidogenic protein beta(2)-microglobulin by capillary electrophoresis and other techniques
No full textSet up of a novel screening method by affinity capillary electrophoresis to find ligands for the amyloidogenic protein beta2-microglobulin. Method validation by surface plasmon resonance and ultrafiltration. Selection of a molecule that preferentially binds a partially structured conformer of the protein, involved in its fibrillogenesis and thus in the onset of dialysis related amyloidosis. The structure of this compound is a starting point for structure-activity relationship studies.
Screening di affinità di una libreria di molecole per la proteina amiloidogenica beta2-microglobulina mediante un metodo innovativo in elettroforesi capillare di affinità. Convalida dei dati mediante surface plasmon resonance e ultrafiltrazione. Individuazione di una molecola che lega preferenzialmente un conformero parzialmente strutturato della proteina, coinvolto nell’insorgenza dell’amiloidosi da dialisi. La sua struttura pone le basi per studi di relazione struttura-attività
DETECTION OF FRAGMENTS OF BETA2-MICROGLOBULIN IN AMYLOID FIBRILS
No full textA major controversy regarding dialysis related amyloidosis (DRA) is about the presence and the role of truncated forms of beta2-microglobulin (beta2M) in the amyloid fibrils. Whereas Linke et al have reported the presence of proteolyzed forms of beta2M in the amyloid deposits in over 12 cases, other groups have not confirmed this finding. A similar analysis conduced in our laboratory with beta2-fibrils obtained from six patients confirms Linke's data
Pharmaceutical strategies against amyloidosis: old and new drugs in targeting a "protein misfolding disease". REVIEW ARTICLE
No full textExtensive review article on the state of the art of drugs used in diseases caused by protein misfolding (amyloidoses). Protein targets are classified according to the mechanism by which they contribute to the onset of the disease whereas drug molecules are grouped according to their respective protein target and their mechanism of action.
E’ questa un’ampia review sulle malattie causate da anomalie del folding proteico e sullo stato dell’arte nell’ambito dell’uso di piccole molecole che possono modificare la cinetica di formazione delle fibre amiloidi o possono facilitarne il riassorbimento.
Le proteine amiloidogeniche sono classificate in base al meccanismo con cui contribuiscono all’insorgenza della malattia di cui sono responsabili, mentre i farmaci di interesse sono raggruppati in base alla proteina bersaglio e al meccanismo d’azione
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