The Dnmt2 enzymes show strong amino acid sequence similarity with eukaryotic and prokaryotic DNA-(cytosine C5)-methyltransferases. Yet, Dnmt2 enzymes from several species were shown to methylate tRNA-Asp and had been proposed that eukaryotic DNA methyltransferases evolved from a Dnmt2-like tRNA methyltransferase ancestor [Goll et al., 2006, Science, 311, 395-8]. It was the aim of this study to ...

Analytical procedures for the determination of selected speciation forms of sulphur have been proposed. The method for conversion of sulphur sols into homogeneous solutions sols allowing simultaneous determination of sulphur either in model solutions or in sols environmental samples has been described. The methods for determination of sulphur sols, elemental sulphur, soluble and insoluble sulph...

The determination of chromium(VI) at high concentrations can be performed spectrophotometrically with 1,5-diphenylcarbazite. The standard determination methods for chromium(VI) in leather like DIN53314 or IUC 18 have a detection limit of 3mg/kg leather. However the detection limit is not enough for lower concentrations. There is a need for lower detection limits because public awareness of hexa...

A microband electrode array modified with palladium-tin bimetallic composite has been developed for nitrate determination. The microband electrode array was fabricated by Micro Electro-Mechanical System (MEMS) technique. Palladium and tin were electrodeposited successively on the electrode, forming a double-layer structure. The effect of the Pd-Sn composite was investigated and its enhancement ...

A semiautomatic determination of glycerol is described, in which luminescence produced by bacterial NADH-linked luciferase is measured by an automatic luminescence analyser (Berthold LB 950 T). The glycerol determination is based on the enzymatic conversion of glycerol to 3-phosphoglycerate, made irreversible by the presence of arsenate. NADH, formed in the glycerol-3-phosphate and glyceraldehy...

A novel simple, sensitive and rapid kinetic-spectrophotometric method for the determination of trace amounts of nitrite is proposed. The method is based on its catalytic effect on the oxidation of congo red (CR) by potassium bromate in acidic solution. The oxidation reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of CR at a suitable λmax = 570 nm for the...

Acylaminoacyl peptidase from Aeropyrum pernix is a homodimer that belongs to the prolyl oligopeptidase family. The monomer subunit is composed of one hydrolase and one propeller domain. Previous crystal structure determinations revealed that the propeller domain obstructed the access of substrate to the active site of both subunits. Here we investigated the structure and the kinetics of two mut...

this study demonstrates the use of a selective and sensitive voltammetric sensor for determination of acetaminophen (ac). this was  performed by modifying a glassy carbon electrode with composite film of poly(4-vinylpyridine) and graphene sheet (p4vp/gr-gce). the redox peak currents of ac increased significantly at p4vp/gr-gce. the result was achieved by the synergistic effect of combined elect...

the conducting polymer films have been widely applied in the field of electrochemistry owing to their goodstability, permselectivity, unique physical and chemical properties. a novel nano-au/poly (4-aminobenzoicacid) (paba) film modified carbon paste electrode was fabricated for sensitive detection of acetaminophenin this paper. the paba film and nano-au/paba film were characterized by scanning...

the conversion process of heavy hydrocarbons to the valuable products such as gasoline is an important operation in the oil refineries.one important process is the “fluidized catalytic cracking” (fcc).feed injection in fcc process has an important role in the selectivity and properties of the products.performance of the feed injection system is dependent on the atomizers.the size and contributi...