BACKGROUND We recently showed improved between-subject variability in our [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) experiments using a Michaelis-Menten transport model to calculate the metabolic tumor glucose uptake rate extrapolated to the hypothetical condition of glucose saturation: MRglucmax=Ki*(KM+[glc]), where Ki is the image-derived FDG uptake rate constant, ...

In this study, lipid-deprived residuals of microalgae were hydrolyzed for the production of reducing sugars by using the recombinant Bacillus cellulosome, carrying eight genes from the Clostridium thermocellum ATCC27405. The obtained cellulosome was found to exist mostly in the broth supernatant with a cellulosome activity of 2.4 U/mL. Furthermore, the Michaelis-Menten constant (Km) and Vmax of...

238 / 250 Introduction: 453 / 750 Discussion: 1478 / 1500 Nonstandard abbreviations used are: Clint,app apparent intrinsic clearance; CYP, cytochrome P450; FMO, flavin-containing monooxygenase; HLM, human liver microsomes; HPLC, highperformance liquid chromatography; KM, Michaelis Menten constant; LC-MS, liquid chromatography mass spectrometry; MS, mass spectrometry; NMR, nuclear magnetic reson...

Errors in the numerical values of activation or normal enthalpies, entropies and free enthalpies calculated from Arrhenius or van't Hoff plots, respectively, are due to the neglect of equidimensionality in equations, or to inappropriate approximations. The logarithmization of dimensioned quantities should be avoided, which demands the use of relative concentrations if a change in mole number oc...

Real time monitoring of electrolyte resistance changes during hydrolysis of 4-nitrophenylphosphate (pNPP) by alkaline phosphatase (ALP) bound on paramagnetic-beads was performed into a small dielectric channel. The reaction kinetic fit with a non-competitive substrate-inhibition equation. Michaelis-Menten apparent constant, KM(app), was determined as 0.33±0.06mM and the maximum apparent rate, V...

The involvement of FMO in the N-oxygenation of CLZ was investigated by use of purified FMOs and human liver microsomes that contained the mean amount of immunoreactive FMO3 relative to other human liver microsomal preparations in a liver bank. In the microsomal preparation the involvement of FMO was indicated through enzyme inhibition by methimazole, heat inactivation, and protection against he...

In this study, partially purified K+-H+ ATPase from frog gastric mucosa were obtained by using differential and density gradient centrifugation. Optimum activity of K+-H+ ATPase (Vmax), Michealis-Menten constant (Km) and Hill coefficient (h) were found as 83.3 mumol Pi.mg prot-1.h-1, 95.2 microM and 0.91, respectively. Enzyme preparations were more stable in glycerol solutions stored at -40 deg...

A method based on the rate of depletion of a nutrient from solution was developed to characterize nutrient flux of plant roots. Nutrient concentration of the solution was measured at a series of time intervals to describe the complete depletion curve. An integrated rate equation, based on a Michaelis-Menten model, was developed and fit to the data of the depletion curve using a least-square pro...

DL-Malic acid-grown cells of the yeast Hansenula anomala formed a saturable transport system that mediated accumulative transport of L-malic acid with the following kinetic parameters at pH 5.0: Vmax, 0.20 nmol.s-1.mg (dry weight)-1; Km, 0.076 mM L-malate. Uptake of malic acid was accompanied by proton disappearance from the external medium with rates that followed Michaelis-Menten kinetics as ...

The response of an amperometric biosensor at mixed enzyme kinetics and diffusion limitations was modelled digitally in the case of substrate inhibition. Digital simulations were carried out using a finite difference technique. Calculations showed complex kinetics of biosensor response. At low enzyme activity and substrate concentration (S0), the response of the sensor looks like it is limited b...