Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (K(m), 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (K(m), 5-25 mm) and a higher (3- to 5-fold)...

this study describes a new simple, sensitive and selective catalytic kinetic spectrophotometricmethod for the determination of vanadium (v). the method is based upon the catalytic effect ofvanadium (v) on the oxidation of carminic acid by bromate in sulfuric acid media. the reaction wasfollowed spectrophotometrically by measuring the decrease in absorbance at 490 nm and thedependence of sensiti...

A kinetic-spectrophotometric procedure is reported for determination of trace amounts of Ag(I). This method is based on catalytic effect of silver ion on the oxidation of congo red by potassium peroxodisulphate at pH=3.4 and 30 oC in the presence of 1,10-phenanthroline as an activator. The reaction was followed spectrophotometrically by measuring the rate of change in absorbance ...

We study the glycosylation processes that convert initially toxic substrates to nutritionally valuable metabolites in the flavonoid biosynthesis pathway of tomato (Solanum lycopersicum) seedlings. To estimate the reaction rates we use ordinary differential equations (ODEs) to model the enzyme kinetics. A popular choice is to use a system of linear ODEs with constant kinetic rates or to use Mich...

The cyclin D1.CDK4-pRb (retinoblastoma protein) pathway plays a central role in the cell cycle, and its deregulation is correlated with many types of cancers. As a major drug target, we purified dimeric cyclin D1.CDK4 complex to near-homogeneity by a four-step procedure from a recombinant baculovirus-infected insect culture. We optimized the kinase activity and stability and developed a reprodu...

The article is focused on the aspects of using micro-catalytic pulse reactors for studying gas-phase reactions. A literature review includes data regarding different types of micro-catalytic pulse reactor applications in heterogeneous catalysis and the techniques used for estimating kinetic parameters are summarized. The experimental part describes the adaptation of a pyrolysis chromatograph to...

The importance of heterogeneous catalysis in modern life is evidenced by the fact that numerous products and technologies routinely used nowadays involve catalysts in their synthesis or function. The discovery of catalytic materials is, however, a non-trivial procedure, requiring tedious trial-and-error experimentation. First-principles-based kinetic modelling methods have recently emerged as a...