Argininosuccinase from normal human liver was purified and characterized. The properties of this enzyme were compared to those of argininosuccinase from bovine liver. The molecular weight of the native human liver enzyme is 200,000 as determined by gel filtration. Polyacrylamide disc gel electrophoresis of the enzyme, dissociated by sodium dodecyl sulfate, indicated that it exists as a tetramer...

1. The formation of adenosine 5'-phosphate, guanosine 5'-phosphate and inosine 5'-phosphate from [8-(14)C]adenine, [8-(14)C]guanine and [8-(14)C]hypoxanthine respectively in the presence of 5-phosphoribosyl pyrophosphate and an extract from Ehrlich ascites-tumour cells was assayed by a method involving liquid-scintillation counting of the radioactive nucleotides on diethylaminoethylcellulose pa...

The present study was undertaken to evaluate the characteristics of pectin methylesterase produced from Aspergillus niger. enzyme had a molecular weight 59.668 kDa. exhibited maximum activity at 45°C. lost most its initial after 20 min incubation 75°C. Optimal and stability occurred pH 4, with more than 90 % retained 10 5. Michaelis constant (Km) found equal (1) mg/ml, whereas, velocity (Vmax) ...

We demonstrate the versatility of Al2O3-passivated Si nanowire devices ("nanoribbons") in the analysis of enzyme-substrate interactions via the monitoring of pH change. Our approach is shown to be effective through the detection of urea in phosphate buffered saline (PBS), and penicillinase in PBS and urine, at limits of detection of <200 μM and 0.02 units/mL, respectively. The ability to extrac...

This current study addresses the effect of diazinon on reversible kinetic parameters such as Michaelis-Menten constant (KS) and Vmax of bovine retinal acetylcholinesterase (AChE). The Ks for the hydrolysis of acetylthiocholine iodide by AChE was increased while Vmax was decreased than the control value in the presence of the diazinon. A LineweaverBurk plot, Dixon plot and their secondary replot...

The ecological forecasting of microorganisms and water quality dynamics in Krasnoyarsk reservoir is based on knowledge of dependence of specific growth rate (SGR) on limiting substrata. It investigated the influence of soil extract on the growth autochtonic bacterioplankton of Krasnoyarsk reservoir. The maximum SGR and Michaelis-Menten constant (on chemical oxidation decomposition (COD) permang...

Wide ranges of growth yields on sulfur (from 2.4 x 10(10) to 8.1 x 10(11) cells g(-1)) and maximum sulfur oxidation rates (from 0.068 to 1.30 mmol liter(-1) h(-1)) of an Acidithiobacillus ferrooxidans strain (CCM 4253) were observed in 73 batch cultures. No significant correlation between the constants was observed. Changes of the Michaelis constant for sulfur (from 0.46 to 15.5 mM) in resting ...

The main alkaline phosphatase isoenzymes of human bile have been purified by DEAE-cellulose chromatography. Characteristics of the isoenzymes, such as electrophoretic mobility before and after butanol extraction, Michaelis constant, and change in electrophoretic mobility following exposure to neuraminidase have been studied and compared with isoenzymes from other sources. The results show that ...

We have isolated an enzyme, phenylalanine ammonia-lyase (EC 4.3.1.5.), from the rootlets of Zea mays var. СЕ-IV. After partial purification by fractional salting out with ammonium sulfate and gel chromatography on Sephadex G-100, we obtained a preparation of a 40-fold greater specific activity than that of the crude homogenate. We hbve determined the ap­ parent Michaelis constant and the activa...