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Polygalacturonases (EC 3.2.1.15) hydrolyze the α-1,4-glycosidic linkages in polygalacturonic acid chains. The interest on specific inhibitors of pectinase and the versatility of magnetic support for enzyme immobilization endorsed the preparation of an immobilized enzyme reactor (IMER). This work presents the synthesis of CoFe(2)O(4) amino-derivatives, which was employed as the support for the immobilization of pectinases from Leucoagaricus gongylophorus. Amino-functionalized CoFe(2)O(4) was obtained from glyceryl-derivatized CoFe(2)O(4) and was characterized by infrared spectroscopy and electronic microscopy. The immobilized enzyme maintained the same thermal, chemical and kinetic behaviour of the free enzyme (T(opt) 60 °C; pH(opt) 5.0; K(app)(M) = 0.5 mg min(-1); V(app)(M) ≈ 5.0 μmol min(-1) mL(-1)). The straightforward synthesis of CoFe(2)O(4) derivatives and the efficiency of immobilization offer wide perspectives for the use of the developed new IMER.

Heterobimetallic compounds [Ru(g 5 -Cp)(dppf)X] (X 5 Cl, Br, I and N 3 ): synthesis, electrochemical analysis, and the crystal structure of [Ru(g 5 -Cp)(dppf)I] [dppf 5 1,1 0 -bis- (3) and [Ru(g 5 -Cp)(dppf)N 3 ] (4) were obtained by reactions of [Ru(g 5 -Cp)(PPh 3 ) 2 Cl] with 1,1 0 -bis(diphenylphosphino) ferrocene (dppf) and characterized by IR, NMR ( 1 H, 13 C and 31 P), 57 Fe Mössbauer spectroscopy and cyclic voltammetry. Additionally, the compound (3) was structurally characterized by X-ray crystallography, and the results were as follows: orthorhombic, Pbca, a = 18.2458 (10), b = 20.9192(11), c = 34.4138(19) Å , a = b = c = 90°, V = 13135.3(12) Å 3 and Z = 16.

Natural terpenes, (-)-limonene and (+)-carvone, can be epoxidized by peroxyacetic acid (PAA) at room temperature if a dinuclear manganese(IV) complex with 1,4,7-trimethyl-1,4,7-triazacyclononane (L), [Mn 2 L 2 O 3 ] [PF 6 ] 2 , is used as a catalyst. The total yield of the epoxides based on the consumed olefins are 97 and 95%, respectively. A kinetic study of the dec-1-ene and cyclohexane oxygenations including the investigation of their simultaneous competitive oxidation was carried out. The olefin epoxidation rate does not depend on dec-1-ene concentration and the dec-1-ene concentration does not affect the rate of cyclohexane oxidation. The cyclohexane oxidation rate is proportional to the alkane concentration. The kinetic analysis led to the conclusion that two species X 1 and X 2 are generated in the system, and there is no their mutual interconversion. The rate equation for the dec-1-ene epoxidation was proposed: W = k +1 [cat] [PAA], where cat is the initial manganese complex or its derivative, and the constant was determined: k +1 = 3.5 mol -1 dm 3 s -1 . Species X 1 is apparently an effectively epoxidizing manganese peroxo derivative whereas species X 2 is an alkane hydroxylating manganese oxo complex.

The present study aimed to purify and characterize one polygalacturonase from L. gongylophorus (PGaseLg), the symbiotic fungus of Atta sexdens. The enzyme was isolated by salting out of crude extract followed by two chromatographic steps. PGaseLG was identified with MS analysis and molecular exclusion chromatography revealed the monomeric nature of a protein with an estimated molecular weight of about 39 kDa. PGaseLg has an optimum temperature of 60˚C and optimum pH activity at 5.0. Using polygalacturonate as a substrate, the calculations of KM, Vmax and kcat were 0.65 mg•mL −1 , 1800 μmol•min −1 •mg −1 and 35.97 s −1 , respectively. The enzyme was stable for more than 3 h at 50˚C at pH 5.0; otherwise, at lower or higher pH values, the PGaseLg was less stable. The influence of several metals, EDTA and β-mercaptoethanol on enzyme activity was also determined. Thin layer chromatography (TLC) analyses indicated that PGaseLg is an exopolygalacturonase.