Direct electrochemistry of glucose oxidase (GOD) was achieved when an ionic liquid/GOD-Polyhydroxy-C60 functional membrane was confined on a glassy carbon electrode (GCE). The cyclic voltammograms (CVs) of the modified GCE showed a pair of redox peaks with a formal potential (E°') of - 329 ± 2 mV. The heterogeneous electron transfer constant (k(s)) was 1.43 s-1. The modified GCE response to glu...

The kinetics of the activation of Glu- and Lys-plasminogen by single-chain urokinase (sc urokinase) derived from the transformed human kidney cell line TCL-598 have been studied and compared with two-chain urokinase (tc urokinase). Plasminogen activation was determined by the increase in fluorescence polarization of fluorescein-labeled aprotinin, a high affinity inhibitor of plasmin. This metho...

Sodium-alanine cotransport was investigated in single isolated proximal tubule cells from rabbit kidney with the whole-cell current recording technique. Addition of L-alanine at the extracellular side induced an inward-directed sodium current and a cell depolarization. The sodium-alanine cotransport current was stereospecific and sodium dependent. Competition experiments suggested a common cotr...

Adenylosuccinate synthetase (IMP:L-aspartate ligase (GDP), EC 6.3.4.4) plays an important role in purine biosynthesis catalyzing the GTP-dependent conversion of IMP to AMP. The enzyme was purified from the cytosol of Dictyostelium discoideum using GTP-agarose chromatography as the critical step. It has an apparent molecular mass of 44 kDa. Monoclonal antibodies identified several forms of the e...

The effects of [Na(+)] or [K(+)] on Na, K-ATPase activity of FW-acclimated and SW-acclimated tilapia, puffer and milkfish were examined in gill homogenates. [Na(+)] or [K(+)] stimulated Na, K-ATPase hydrolyzing ATP in all experimental groups. ATP hydrolysis stimulated by [Na(+)] or [K(+)] followed Michaelian-Menten kinetics. Km values for [K(+)] (i.e., Km(K)), were lower in SW- than FW-acclimat...

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...

The uptake kinetics of strontium in the common carp (Cyprinus carpio) were characterized in vivo, exposing preacclimated fish to a wide range of Sr21 (0.27 mM–10.0 mM) and Ca21 (10 mM–10 mM) concentrations in water; 85Sr, 45Ca, and 47Ca were used as tracers in determining the uptake, and the possibility of adsorption of the tracers to the exterior of the fish were verified. The uptake rates wer...

Proteorhodopsin (PR) is a light-powered proton pump identified by community sequencing of ocean samples. Previous studies have established the ecological distribution and enzymatic activity of PR, but its role in powering cells and participation in ocean energy fluxes remains unclear. Here, we show that when cellular respiration is inhibited by depleting oxygen or by the respiratory poison azid...

supplemented with 10% horse serum. The cells grew ex ponentially with a doubling time of 16 to 17 hours, had a cell volume (mean ±S.E.) of 2313 ±89 cu /tm, and were cloned in soft agar with a cloning efficiency of 68.7 ±6.3%. Sensitivity to the alkylating agent nitrogen mustard (HN2) was comparable to that observed previously with LSI78Y murine lymphoblasts; the D0 (the dose of drug reducing...