A new method is described for plotting kinetic results for inhibited enzyme-catalysed reactions. It provides a simple way of determining the inhibition constant, K'(i), of an uncompetitive, mixed or non-competitive inhibitor.

Activated sludge process is a highly effective and commonly adapted method of aerobic biological treatment systems and is normally designed on the basis of simplified hydraulic related parameters. Designs of biological treatment systems based on hydraulic considerations are not adequate to ensure efficient operation. This is due to the wide variation in the composition of wastewater and the com...

A number of experimental and theoretical papers accounted almost exclusively for two channels in the reaction of atomic hydrogen with methanol: H-abstraction from the methyl (R1) and hydroxyl (R2) functional groups. Recently, several astrochemical studies claimed the importance of another channel for this reaction, which is crucial for kinetic simulations related to the abundance of molecular c...

The reaction of ascorbate-reduced Pseudomonas cytochrome oxidase with oxygen was studied by using stopped-flow techniques at pH 7.0 and 25 degrees C. The observed time courses were complex, the reaction consisting of three phases. Of these, only the fastest process, with a second-order rate constant of 3.3 X 10(4) M-1.S-1, was dependent on oxygen concentration. The two slower processes were fir...

Introduction: Dynamic contrast enhanced MRI (DCE-MRI) has been shown its ability to noninvasively assess characterization of tumor by the kinetic parameters, such as volume transfer constant (K) and rate constant (kep). The Tofts and Kermode (TK) model [1] and modification of Tofts and Kermode (mTK) model [2] are both popular pharmacokinetic models. Nonlinear least-squares (NLSQ) method is ofte...

The membrane-active enzyme phospholipase D (PLD) catalyzes the hydrolysis of the phosphodiester bond in phospholipids and plays a critical role in cell signaling. This catalytic reaction proceeds on lipid-water interfaces and is an example of heterogeneous catalysis in biology. Recently we showed that planar lipid bilayers, a previously unexplored model membrane for these kinetic studies, can b...

A differential scanning calorimetry study on the thermal denaturation of concanavalin A at pH 5.2 where it exists in the dimeric form was carried out. The calorimetric transitions were observed to be irreversible and the transition temperature of the protein increased with increasing scan rate, indicating that the thermal denaturation process is under kinetic control. The thermal unfolding, and...

The sphingomyelinase (Sphmase) activity degrading sphingomyelin (Sphm) monolayers shows a slow-reaction latency period before exhibiting constant rate catalysis. These two kinetic regions are regulated independently by the lateral surface pressure and by lipids that are biomodulators of cell function such as ceramide, glycosphingolipids, fatty acids, and lysophospholipids. Knowledge of the inte...

OBJECTIVES The aim of this article is biochemical and kinetic characterization of CTX-M-43, a natural Asp-240-->Gly mutant of CTX-M-44 (ex Toho-1), from a clinical isolate of Acinetobacter baumannii isolated in a Bolivian hospital. METHODS Steady-state kinetic parameters (K(m) and k(cat)) were determined for a large pattern of substrates. Analysis of inactivators and transient inactivators wa...