The enzymatic hydrolysis of urea by jack bean urease was investigated at 25 °C over the pH range 4–9. Reaction rate data were found to be well described by a modified Michaelis-Menten equation with a pH-dependent rate coefficient and a product inhibition term. The influence of pH on activity was interpreted in terms of perturbation of the enzyme distribution among three differently protonated f...

Argininosuccinase from normal human liver was purified and characterized. The properties of this enzyme were compared to those of argininosuccinase from bovine liver. The molecular weight of the native human liver enzyme is 200,000 as determined by gel filtration. Polyacrylamide disc gel electrophoresis of the enzyme, dissociated by sodium dodecyl sulfate, indicated that it exists as a tetramer...

Motivated by investigating multistationarity in biochemical systems, we address saddle-node bifurcations for chemical reaction networks endowed with general kinetics. At positive equilibria, identify structural network conditions that guarantee the bifurcation behavior, and develop a method to proper parameters. As relevant example, explicitly provide such parameters Michaelis–Menten Hill Examp...