A specialized kinetic analysis of real-time hyperpolarized [1,1,2,2-D4, 1-(13)C]choline (13)C-magnetic resonance spectroscopy enabled the determination of initial rates of metabolic enzyme activity (choline oxidase), enzyme-substrate affinity (Km), and inhibition. In a clinical MRI scanner, metabolite levels lower than 16 μM were detected at a temporal resolution of 1 s.

Active site titration by a reversible tight-binding inhibitor normally depends on prior knowledge of the inhibition constant. Conversely, the determination of tight-binding inhibition constants normally requires prior knowledge of the active enzyme concentration. Often, neither of these quantities is known with sufficient accuracy. This paper describes experimental conditions under which both t...

Generic simple and sensitive universal enzyme immunoassay approach for the determination of small analytes has been developed to avert the problems associated with small molecule immobilization onto solid phases. The developed assay employed a heterogeneous non-competitive binding format. The assay used anti-analyte antibody coupled to polyacrylamide beads as a solid-phase and beta-d-galactosid...

A cyclic voltammetric simulation that can be applied to an electrochemically mediated enzyme reaction involving any substrate and mediator concentrations was developed. Concentration polarization of the substrate in the vicinity of an electrode was considered as well as mediator concentration. Reversible and quasi-reversible electrochemical reactions with one electron followed by an enzyme reac...

Magnetic silica aerogel in hydrophobic and hydrophilic forms were used as support to immobilize Candida rugosa lipase by adsorption method. Response surface methodology (RSM) was employed to study the effects of the three most important immobilization parameters, namely enzyme/support ratio (0.3-0.5, w/w), immobilization time (60-120 min) and alcohol percentage (20-40, %v/v) on the specific act...

besides the high starch content, sweet potato contains endogenous amylases where the two predominants are - and β-amylases. sweet potato is thought to be a promising source of β -amylase since β -amylase is one of the major protein in the tubers. this investigation has focused on the properties of β amylase from white-flesh sweet potato that has been grown in iran as a potential source for indu...

Amlodipine is a calcium channel antagonist of the dihydropyridine group. It is effective for treating hypertension, chronic stable angina, and vasospastic angina. However, it is difficult clinically to pinpoint the maximum dosage for antihypertensive activity of the drug without having parallel data on the plasma drug concentrations. The methods for assaying amlodipine are either gas chromatogr...

The EMIT homogeneous enzyme immunoassay for the determination of thyroxine (T4) was adapted to an automatic analyser (Type Kem-O-Mat) and compared with a conventional radioimmunoassay. Sera from 92 patients whose thyrometabolic status was being examined, and control sera with 3 different T4 concentrations were analysed by both methods. Day-to-day analyses of the control sera gave variation coef...

most of the biological phenomena are influenced by intermolecular recognition and interaction. thus, understanding the thermodynamics of biomacromolecule ligand interaction is a very interesting area in biochemistry and biotechnology. one of the most powerful techniques to obtain precise information about the energetics of (bio) molecules binding to other biological macromolecules is isothermal...