RESUMEN
Five indigenous Aspergillus flavus strains MTCC-2206, 1884, 1883, 1783 and 2456 were screened for the secretion of quercetinase. Fungal strains MTCC-2206, 1884, 1883, and 1783 were found to secrete the quercetinase in the range of 0.24-0.36 enzyme unit/mL of the culture medium, while MTCC-2456 secreted only 0.04 enzyme unit/mL. The enzymatic characteristics of quercetinase were determined. The Km values using quercetin as the substrate were 12.5 microM, 14.0 microM, 12.5 microM and 13.0 microM for the quercetinase produced by MTCC-2206, 1884, 1883 and 1783, respectively. The pH optima for the above enzymes were 6.5, 6.5, 6.0 and 6.0 and temperature optima were 45, 40, 45 and 50 degrees C, respectively. The partial purification from only one strain MTCC-2206 was achieved (nearly 3-fold purification).
Asunto(s)
Aspergillus flavus/enzimología , Dioxigenasas/química , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Cinética , Peso MolecularRESUMEN
Solanum melongena fruit juice contains peroxidase activity of the order of 0.125 IU/mL. A method for the 11-fold purification of the enzyme was developed. The Km values of the peroxidase for the substrates guaiacol and hydrogen peroxide were 6.5 mM and 0.33 mM, respectively. The pH and temperature optima were 5.5 and 84 degrees C, respectively using guaiacol as the substrate. Sodium azide and phenyl hydrazine inhibited the enzyme competitively.
Asunto(s)
Bebidas , Relación Dosis-Respuesta a Droga , Frutas , Guayacol/farmacología , Peróxido de Hidrógeno/farmacología , Concentración de Iones de Hidrógeno , Cinética , Peroxidasas/química , Fenilhidrazinas/farmacología , Azida Sódica/farmacología , Solanum melongena/enzimología , TemperaturaRESUMEN
Secretion of ligninperoxidase [E.C.1.11.1.7] by Penicillium citrinum, Fusarium oxysporum and Aspergillus terreus in liquid culture growth medium has been demonstrated. Enzymatic characteristics like Km, pH and temperature optima using veratryl alcohol as the organic substrate of ligninperoxidases from above sources have been determined. Km values using veratryl alcohol as substrate for enzymes from P. citrinum, F. oxysporum and A. terreus were 69, 64 and 60 microM respectively. Km values using H2O2 as the variable substrate were 64, 72 and 80 microM.The pH optima were 4.0, 2.3 and 2.0 respectively. The values of temperature optima were 30 degrees, 25 degrees and 22 degrees C for the enzymes from P. citrinum, F. oxysporum and A. terreus respectively.