The role of peroxidase in the enzymatic oxidation of phenolic compounds to quinones from Luffa aegyptiaca (gourd) fruit juice

Luffa aegyptiaca fruit juice was used as a low purity source of enzyme, which contained peroxidase activity of 180 IU/mL. The results of UV/VIS and IR studies suggested that L. aegyptiaca fruit juice works efficiently in the enzymatic conversion of phenolic compounds, namely guaiacol, m-cresol, p-cresol, o-cresol, anisole, resorcinol, catechol, pyrogallol, hydroquinone, veratryl alcohol and phoreguicinol to quinones at 30°C. The p-cresol and pyrogallol were converted to quinones more efficiently as compared to other phenolic compounds. Determination of enzymatic characteristic properties such as Michaelis–Menten constant (Km), temperature optima and pH optima using different phenolic compounds, indicated p-cresol as a potential substrate for the peroxidase enzyme assay at room temperature, whereas guaiacol, which is widely used as a substrate for enzyme assay, has a higher temperature optima at 60°C for its maximum catalytic activity. Enzyme activity is inhibited by sodium azide using different phenolic substrates in the reaction mixture

Synthesis of Oxovanadium(IV) Complexes with Tetraaza Coordinating Ligands

Oxovanadium(IV) complexes of the type [VO(mac)]SO4 (where mac = tetraaza macrocyclic ligands derived by condensation of thenil with 1,4-diaminobenzene or 3,4-diaminopyridine and their reaction with β-diketones) have been prepared using vanadyl ion as kinetic template. The prepared macrocyclic complexes were characterized by elemental analyses, molar conductance, magnetic moments, and infrared, electronic, and electron spin resonance data. From the spectroscopic studies, five-coordinate square-pyramidal geometry for the VO2+ complexes have been proposed wherein derived ligands act as tetradentate chelating agents

Purification and characterization of novel manganese peroxidase from <i>Trichoderma parestonica</i> and its bio-conversion study of toxic arylamine

Trichoderma parestonica is a novel source of manganese peroxidase (MnP), [E.C.1.11.1.13] enzyme. The following was the sequence in which T. parestonica induced the production of MnP in the liquid culture medium: rice husk, corncob, sawdust, coir-dust and dried luffa on days 3, 4, 5, 2 and 3, respectively. The molecular weight of the enzyme was found to be 45kDa, determined from SDS-PAGE analysis which was further confirmed by mass analysis and was found to be 51.9kDa. Enzyme characterization parameters like optimum pH, temperature, Km, Kcat and catalytic efficiency are 5, 20ᵒC, 0.014mM (for Mn2+) and 0.028mM (for H2O2), 23.9 S-1 and 1.7 μM-1 S-1 respectively. Effect of various metal ions, such as bivalent Copper(Cu), Cobalt(Co), Mercury(Hg), Nickel(Ni), Cadmium(Cd), trivalent Chromium(Cr), Iron(Fe), Tetra-valent cerium(Ce), Penta-valent vanadium(V) and hexavalent molybdenum(Mo) the enzyme-catalyzed steady-state velocity was studied. The inhibition constant and nature of inhibition by these metal ions were determined. In the current investigation, MnP catalytic activities demonstrated that it could effectively catalyze the oxidation of phenols, aromatic amines and wastewater treatment. This communication suggested potential pathways for aromatic amine bioconversion mediated by MnP</p