The pre-steady-state kinetics of phosphate formation from 5-enolpyruvylshikimate 3-phosphate catalysed by Escherichia coli chorismate synthase (EC 4.6.1.4) were studied by a rapid-acid-quench technique at 25 degrees C at pH 7.5. No pre-steady-state 'burst' or 'lag' phase was observed, showing that phosphate is released concomitant with the rate-limiting step of the enzyme. The implications of t...

Abstract: Fhosphofructokinase has been identified and purified from extracts of Rhodotorula glutinlus. Kinetic studies of the enzyme indicated high eooperativity with respect to fructose 6-phosphate. The kinetics for ATP shows no cooperativity as indicated by the hyperbolic behavior of the enzyme. The enzyme is inhibited by ADF. Citrate and phosphate have no effect on the enzyme activity. The r...

6,7-Dideoxy-D-gluco-heptonic-7-phosphonic acid, the isosteric phosphonate analogue of gluconate 6-phosphate, was prepared by incubation of the corresponding analogue of glucose 6-phosphate with glucose 6-phosphate dehydrogenase and NADP+ in the presence of an enzyme NADPH-NADP+ recycling system. The analogue of gluconate 6-phosphate is a substrate for yeast gluconate 6-phosphate dehydrogenase, ...

The kinetics of phosphate adsorbed on waste iron sludge was investigated in this study. Static batch adsorption experiments were performed at different initial phosphate concentrations, initial pH and temperature of solution. The initial adsorption rate increased with increasing the phosphate concentration. A shorter time, however, was required to reach adsorption equilibrium at low phosphate c...

Our results show that the phosphate ion is a nonlinear competitive inhibitor of Pinus pinea isocitrate lyase. In addition, this compound induces a sigmoidal response of the enzyme, which usually exhibits standard Michaelis-Menten kinetics. This peculiar behavior of P. pinea isocitrate lyase could be explained by a dimer (two-site) model, in which phosphate binds cooperatively, but the affinity ...

This in vitro microperfusion study examined the effects of growth hormone and insulin-like growth factor I (IGF-I) on proximal convoluted tubule (PC1) transport. Tubules were perfused with an ultrafiltrate-like solution and bathed in a serumlike albumin solution. Neither a physiologic (5 X 10-10 M), nor a pharmacologic (5 X 10jM) dose of growth hormone had an effect on PCT phosphate or bicarbon...

Drug release kinetics plays an important role in determining the mechanism of drug release, which in turn helps in formulating controlled/sustained release formulations.In our study, different concentrations of green tea polyphenols (GTP) were encapsulated into casein nanoparticles which showed a maximum encapsulation efficiency (76.9%) at a GTP concentration of 5 mg/mL. The casein nanopa...

Drug release kinetics plays an important role in determining the mechanism of drug release, which in turn helps in formulating controlled/sustained release formulations.In our study, different concentrations of green tea polyphenols (GTP) were encapsulated into casein nanoparticles which showed a maximum encapsulation efficiency (76.9%) at a GTP concentration of 5 mg/mL. The casein nanopa...