Escherichia coli serA-encoded 3-phosphoglycerate (3PG) dehydrogenase catalyzes the first step of the major phosphorylated pathway of L-serine (Ser) biosynthesis. The SerA enzyme is evolutionarily related to the pdxB gene product, 4-phosphoerythronate dehydrogenase, which catalyzes the second step in one branch of pyridoxal 5'-phosphate coenzyme biosynthesis. Both the Ser and pyridoxal 5'-phosph...

An in vitro technique for perfusion of the intestinal vasculature and lumen was developed and used to measure calcium (Ca) fluxes across the intestinal mucosa of the marine teleost, the Atlantic cod {Gadus morhua). Saturable and nonsaturable components of the calcium influx and efflux were determined. The calcium influx had one passive component and one saturable component, following Michaelis-...

The contributions of pulmonary endothelial and blood cells to the removal of adenosine during a single passage through the rabbit pulmonary circulation were investigated. In the isolated, blood-free perfused rabbit lung in situ, single pass pulmonary removal of [3H]-adenosine injected into the pulmonary artery was accomplished by a low-affinity, saturable process yielding apparent Michaelis-Men...

A novel amperometric nitrite (NO2 − ) sensor was developed based on immobilization of hemoglobin (Hb) on a graphene nanosheet modified electrode by chitosan-N, N-Dimethylformamide (CS-DMF) hydrogel. The surface morphologies of the modified electrode were characterized by SEM, and direct electrochemistry of Hb on the graphene nanosheet-based electrode were investigated by cyclic voltammetry. The...

Glucose is the major substrate that sustains normal brain function. When the brain glucose concentration approaches zero, glucose transport across the blood-brain barrier becomes rate limiting for metabolism during, for example, increased metabolic activity and hypoglycemia. Steady-state brain glucose concentrations in alpha-chloralose anesthetized rats were measured noninvasively as a function...

Ruminally undegraded protein (RUP) values of blood meal (n = 2), hydrolyzed feather meal (n = 2), fish meal (n = 2), meat and bone meal, and soybean meal were estimated using an in situ method, an inhibitor in vitro method, and an inhibitor in vitro technique applying Michaelis-Menten saturation kinetics. Degradation rates for in situ and inhibitor in vitro methods were calculated by regression...

Abstract Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on decolorization efficiency evaluated. optimal conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. kinetic fitted Michaelis–Menten model (Vmax = 111.11 mg L-1 h-1 Km 448.3 L-1). bacterium also able degrade benzidine...

objective(s): enzyme immobilization via nanoparticles is perfectly compatible against the other chemical or biological approximate to improve enzyme functions and stability. in this study lactoperoxidase was immobilized onto silica-coated magnetite nanoparticles to improve enzyme properties in the presence of cadmium chloride as an inhibitor. materials and methods:  the process consists of the ...

Background: Acid phosphatase (ACP) is suggested to be one of the virulence factors in leishmania and a correlation has been reported between Leishmanial acid phosphatase (ACP) activity and the severity of the disease in all types of leishmaniasis including zoonotic cutaneous leishmaniasis (ZCL), which is a polymorphic disease. Objective: Characterization of leishmania and its correlation with t...

This paper summarizes our present theoretical understanding of single-molecule kinetics associated with the Michaelis-Menten mechanism of enzymatic reactions. Single-molecule enzymatic turnover experiments typically measure the probability density f(t) of the stochastic waiting time t for individual turnovers. While f(t) can be reconciled with ensemble kinetics, it contains more information tha...