For some time now, there has been growing interest in pre-steady-state (PSS) kinetic parameters for whatever reasons, the measurement of which needs high-tech equipment capable transient time-scale duration assay. The proposition, however, is that all parameters, PSS and beyond, can be determined with appropriate derivable equations usual Michaelis-Menten (MM) Briggs-Haldane (BH) equations, res...

In the case of a transport system obeying Michaelis-Menten kinetics, completely general relationships are shown to exist between the final ratio of internal and external substrate concentrations, alpha, and the V/Km ratios found in zero-trans-entry, zero-trans-exit and equilibrium-exchange experiments (where V is a maximum substrate flux and Km a substrate half-saturation constant). The proof d...

A model has been used to simulate potassium (K) uptake by wheat in a pot culture experiment. Three soils from India, namely Alfisol, Inceptisol and Vertisol, were differentially K exhausted by Sudan grass (Surghum vulgare var. Sudanensis) for a period of 280 days and were used to simulate potassium uptake by wheat (Triticum aestivum) and also to predict the amounts of K released or fixed during...

Voriconazole is a triazole antifungal used empirically for the treatment of complicated meningitis associated with Cryptococcus neoformans. Biopsy studies show that drug exhibits adequate brain penetration although levels cerebral spinal fluid (CSF) are highly variable. Considering CSF one main surrogates CNS exposure, present work proposed building population pharmacokinetic modeling (popPK) m...

V-ATPases are rotary molecular motors that generally function as proton pumps. We recently solved the crystal structures of the V1 moiety of Enterococcus hirae V-ATPase (EhV1) and proposed a model for its rotation mechanism. Here, we characterized the rotary dynamics of EhV1 using single-molecule analysis employing a load-free probe. EhV1 rotated in a counterclockwise direction, exhibiting two ...

Ureases are amidohydrolases that catalyze the hydrolysis of urea to ammonia and carbamate. In addition enzymatic function, ureases have fungitoxic insecticidal which independent their catalytic activity. Soy (Glycine max) has two main urease isoforms: ubiquitous embryo-specific, latter is present in beans. view potential applications ureases, this work aimed extract, purify, characterize struct...

The conditions under which the Michaelis-Menten equation accurately captures the steady-state kinetics of a simple enzyme-catalyzed reaction is contrasted with the conditions under which the same equation can be used to estimate parameters, KM and V, from progress curve data. Validity of the underlying assumptions leading to the Michaelis-Menten equation are shown to be necessary, but not suffi...

Background: Phospholipases are one of the numerous enzymes found in Naja mossambica venom. They play a major role snakebite envenomation, and also responsible for hydrolysis phospholipid, disrupting membrane integrity. In this study, we evaluated effect Vernonia amygdalina on Phospholipase activity from (Cobra) Results: Partially purified phospholipase had maximal velocity (Vmax) Michaelis Ment...

This paper presents a simple solution to the problem of approximating the calculated curve of reaction progress to the measured curve which is usually disturbed by initial oscillation of auxiliary lactate dehydrogenase (LDH) reaction. The experiments leading to the determination of the apparent Km for phosphoenolpyruvate (PEP) and Vm were performed. For precise estimation of kinetic parameters ...

Conventional analysis of enzyme-catalyzed reactions uses a set of initial rates of product formation or substrate decay at a variety of substrate concentrations. Alternatively to the conventional methods, attempts have been made to use an integrated Michaelis-Menten equation to assess the values of the Michaelis-Menten KM and turnover kcat constants directly from a single time course of an enzy...