The kinetics of the action of fumarase on L-malate and fumarate were investigated at constant ionic strength. This was done to evaluate reports that fumarase follows simple Michaelis-Menten kinetics. However, when pH, buffer concentration and ionic strength are all maintained at constant values, the Lineweaver-Burk plots exhibit pronounced downward curvature, characteristic of negative kinetic ...

In this paper a new model is described for calculating the electric potential field in a long, thin nanochannel with overlapped electric double layers. Electrolyte concentration in the nanochannel is predicted self-consistently via equilibrium between ionic solution in the wells and within the nanochannel. Differently than published models that require detailed iterative numerical solutions of ...

A difference in salt concentration in two solutions separated by a membrane leads to an electrical potential difference across the membrane, also without applied current. A literature study is presented on proposed theories for the origin of this membrane potential (ϕm). The most well-known theoretical description is Teorell-Meyer-Sievers (TMS) theory, which we analyze and extend. Experimental ...

In their seminal works on squid giant axons, Hodgkin, and Huxley approximated the membrane leak current as Ohmic, i.e., linear, since in their preparation, sub-threshold current rectification due to the influence of ionic concentration is negligible. Most studies on mammalian neurons have made the same, largely untested, assumption. Here we show that the membrane time constant and input resista...

A series of diethylmethyl(2-methoxyethyl)ammonium (DEME)-based ionic liquids were prepared using bis(perfluoroalkanesulfonyl)amide (C(n)F(2n+1)SO(2))(2)N anions with different perfluoroalkyl chain lengths (n = 0, 1, 2, 3, and 4), and the influence of the structural variation on their thermal, ion-diffusive (ionic conductivity and viscosity), ion-concentration (molar concentration and ion associ...

The density (d), speed of sound (u) and electrolytic conductivity (Λ) for systems containing acetaminophen, ionic liquid {1-octyl-3-methyl imidazolium bromide, [OMIm] Br} and water have been measured at T = 293.15-308.15 K. The measured data have been applied to calculate, standard partial molar volume ( ), Hepler’s constant , apparent molar isentropic compressibility...

In this research, the interaction of hexadecyl trimahyl ammonium bromide (HTAB) with enzyme ureasehas been investigated comprehensively at different experimental conditions such as ionic strength, proteinconcentration using ion selective membrane electrode of surfactants. The obtained binding isotherms frompotentiometnc studies have been analyzed by different theories such as Wyman binding pote...

The effects of mobility corrections on carrier ampholytes are studied at various ampholyte concentrations to understand protein behavior during IEF. IEF simulations are conducted in the presence of 25 biprotic carrier ampholytes within a pH range of 6-9 after applying the Onsager-Debye-Hückel correction to the carrier ampholytes. Two model proteins with ten charge states but without ionic stren...

Liquid Crystal Phase Transitions of Monodisperse and Bidisperse Suspensions of Rodlike Colloidal Virus A dissertation presented to the Faculty of the Graduate School of Arts and Sciences of Brandeis University, Waltham, Massachusetts by Kirstin Rachael Purdy We experimentally study the role of steric and electrostatic interparticle interactions in monodisperse and bidisperse suspensions of rodl...

The built-in site density of either fixed sites or mobile hydrophobic ion sites determines whether a membrane is permselective for cations or anions of the sample. The molar ratio of the ionophore to the intrinsic or added ionic sites in an ion-selective membrane significantly influences the potentiometric response of ionophore-based electrodes. Consequently, full knowledge of the "site invento...