Résumé
A pectin lyase (PNL, EC 4.2.2.10) produced extracellularly by the strain of Penicillium oxalicum in solid-state fermentation medium containing deoiled mandarin orange peel meal was purified to apparent homogeneity by a protocol that included ammonium sulfate precipitation, DEAE-Sephadex A-50 and Sephadex G-100 chromatography. The enzyme had molecular mass of 50 kD, as determined by SDS- PAGE and showed optimum pH and temperature at 8.0 and 50 degrees C respectively. It had an isoelectric point (pI) of 5.0 and showed a K(m) of 1.1 mg/ml of citrus pectin. The enzyme was strongly inhibited by Mo4+, Ag+ and Pb2+ and also by polyphenolic compounds, in particular tannic acid.
Sujets)
Espace extracellulaire/métabolisme , Fermentation , Penicillium/enzymologie , Polysaccharide-lyases/isolement et purificationRésumé
Plants of the genus Dieffenbachia, very popular as indoor ornamental plants, are known for their toxic as well as therapeutic properties. Their toxic manifestations have been partly attributed to their proteolytic activity. The work described in the present paper shows that stem leaves and petiole of Dieffenbachia maculata Schott, a commonly grown species, contain significant proteolytic activity, different parts showing different types of protease activities. Stem showed the highest enzyme activity and this protease was purified about 55 fold by solvent precipitation, gel filtration and ion exchange chromatography. The enzyme has a relative molecular mass of 61 kDa as determined by SDS-PAGE and has an optimum pH of 8.0 and optimum temperature of 50 degrees C. Effects of various substrates, inhibitors and activators indicate that the enzyme is a cysteine protease with leucylpeptidase activity.
Sujets)
Magnoliopsida/enzymologie , Chromatographie sur gel , Chromatographie d'échange d'ions , Cysteine endopeptidases/composition chimique , Électrophorèse sur gel de polyacrylamide , Masse moléculaire , Structures de plante/enzymologie , Facteurs tempsSujets)
Adulte , Sujet âgé , Femelle , Fractures du col fémoral/étiologie , Humains , Inde/épidémiologie , Mâle , Adulte d'âge moyen , Ostéoporose/complicationsRésumé
Administration of sodium orthovanadate (0.3 mg/ml) through drinking water for 20 days to streptozotocin-induced diabetic rats resulted in reversal of markedly elevated activities of some of the key enzymes of tryptophan-niacin pathway, viz. hepatic and renal aminocarboxymuconate semialdehyde decarboxylase and hepatic tryptophan oxygenase, to normal levels without restoring the elevated blood sugar level to normal state. However vanadate administration to normal rats did not cause any significant change.
Sujets)
Animaux , Glycémie/métabolisme , Diabète expérimental/sang , Femelle , Rein/effets des médicaments et des substances chimiques , Foie/effets des médicaments et des substances chimiques , Rats , Rat Wistar , Vanadates/pharmacologieRésumé
Ingestion of ethanol by albino rats affected brain liver and plasma tryptophan contents in both normal and diabetic animals, although at different rates. Liver tryptophan was increased in both the groups, whereas tryptophan levels in brain and plasma of normal group were decreased and those of diabetic group were increased after the treatment. Similarly, while hepatic tryptophan dioxygenase activity was decreased in both the groups, activity of hepatic 3-hydroxykynureninase was increased only in normal rats and that of liver picolinic carboxylase was significantly decreased only in the diabetic group after ethanol administration.
Sujets)
Animaux , Diabète expérimental/métabolisme , Éthanol/toxicité , Cynurénine/métabolisme , Mâle , Rats , Lignées consanguines de rats , Tryptophane/métabolismeRésumé
Streptozotocin diabetic rats fed ad libitum exhibited hyperplasia of the small intestine. As compared to the control animals, the intestine of experimental animals grew in weight, length and total RNA and DNA contents. Intestinal cinnabarinate synthase activity in diabetic rats was however significantly lower. Developmental studies in albino rats indicated that, attainment of the terminal and highest activity of the enzyme tends to correspond with cessation of further increase in RNA and DNA contents of the intestine, thereby suggesting a possible relationship between cinnabarinate synthase and the hyperplastic changes observed. It was also observed that some properties of this enzyme, such as Km and Vmax are modified in diabetic condition. The enzyme was purified to apparent homogeneity and some of its kinetic and other properties were studied.
Sujets)
Animaux , Catalase/isolement et purification , Diabète expérimental/enzymologie , Hyperplasie/enzymologie , Intestin grêle/enzymologie , Mâle , Rats , Lignées consanguines de ratsSujets)
Carbone/pharmacologie , Chromatographie/méthodes , Activation enzymatique/effets des médicaments et des substances chimiques , Geotrichum/enzymologie , Glycosidases/biosynthèse , Concentration en ions d'hydrogène , Métaux/pharmacologie , Deuteromycota/enzymologie , Masse moléculaire , Polygalacturonase/antagonistes et inhibiteurs , Pyruvates/pharmacologie , Acide pyruvique , Thiols/pharmacologieRésumé
A strain οf Alternaria alternata (Fr.) Keissl, when grown on wheat bran Czapek Dox medium was found to secrete one neutral and two alkaline proteases. The purified enzymes were found to be endo peptidases, the alkaline proteases being serine proteases and neutral proteases being cysteine proteases. Fructose when added to the culture medium was found to give rise to a new neutral protease at the expense of the neutral protease produced in the absence of fructose and was also found to enhance the production of alkaline proteases. It also appears that fructose modifies the alkaline proteases with respect to some characteristics such as Vmax, Ea etc. Sodium dodecyl sulphate Polyacrylamide gel electrophoresis indicated a significantly altered protein profile in fructose supplemented .medium.