Neural networks and hybrid models were used to study substrate and product inhibition observed in the enzymatic hydrolysis of cellobiose at 40oC, 50oC and 55oC, pH 4.8, using cellobiose solutions with or without the addition of exogenous glucose. Firstly, the initial velocity method and nonlinear fitting with Statistica were used to determine the kinetic parameters for either the uncompetitive ...

Background: Diabetes mellitus is a chronic disease. Decreasing postprandial hyperglycemia by retarding glucose absorption through inhibiting carbohydrates digesting enzymes (α-amylase and α-glucosidase) is one of many approaches used for the management of this disease. This study was aimed at evaluating the normoglycaemic potential of Helianthus annuus leaf. Methods: The effect o...

We examined the effect of adriamycin on kinetics of DNA synthesis catalyzed by DNA polymerase purified from bacteriophage T4-infected Escherichia coli. Two distinct modes of enzyme inhibition occur: uncompetitive and competitive at “low” and “high” drug:DNA nucleotide molar ratios, respectively. Competitive inhibition is not observed unless an unblocked amino group is present on the sugar (daun...

Lactase activity in presence of mono and divalent metal ions, as its cofactors, and some reducing agents was studied. Activation effects of k and Mn were better than other cations and dithiotrethiol was more inhibitor. By inhibition constant, 12.15mMol, the type of inhibition was non-competitive. The kinetic model of Lactase hydrolysis reaction also was determined. Among glucose and galactose a...

The tetrasaccharide heparan sulfate (HS) mimetic PG545, a clinical anti-cancer candidate, is an inhibitor of the HS-degrading enzyme heparanase. The kinetics of heparanase inhibition by PG545 and three structural analogues were investigated to understand their modes of inhibition. The cholestanol aglycon of PG545 significantly increased affinity for heparanase and also modified the inhibition m...

Although approaches to the prediction of drug-drug interactions (DDIs) arising via time-dependent inactivation have recently been developed, such approaches do not account for simple competitive inhibition or induction. Accordingly, these approaches do not provide accurate predictions of DDIs arising from simple competitive inhibition (e.g., ketoconazole) or induction of cytochromes P450 (e.g.,...

Batch kinetic and inhibition studies were performed for the aerobic cometabolism of 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethylene (1,1-DCE), and 1,1-dichloroethane (1,1-DCA) by a butane-grown mixed culture. These chlorinated aliphatic hydrocarbons (CAHs) are often found together as cocontaminants in groundwater. The maximum degradation rates (k(max)) and half-saturation coefficients (...

Two biokinetic models employing the Michaelis-Menten equation for anaerobic reductive dechlorination of tetrachloroethylene (PCE) and trichloroethylene (TCE) were developed. The models were compared with results from batch kinetic tests conducted over a wide range of PCE and TCE concentrations with two different dechlorinating cultures. One model applies Michaelis-Menten kinetics with competiti...