The kinetics of hepatic indocyanine green (ICG) uptake have been analysed in 14 patients with chronic active liver disease. The removal of incremental, submaximal ICG doses were compatible with Michaelis-Menten kinetics in approximately 80% of studies in patients allowing the calculation of the maximal rate of removal (Rmax) and the Michaelis constant (Km). Neither of these variables correlated...

Calcium transport by sarcotubular vesicles (fragmented sarcoplasmic reticulum) from skeletal muscle of rats, rabbits, and humans follows Michaelis-Menten kinetics when studied in systems containing oxalate and low ratios of calcium to vesicle protein. Under these conditions different preparations of vesicles are characterized by their calcium concentrating ability, i.e. the constant level to wh...

3-Deoxy-D-manno-octulosonate aldolase, an inducible enzyme isolated from extracts of 3-deoxy-D-manno-octulosonate-grown Aerobacter cloacae, has been purified approximately 60-fold. The enzyme catalyzes the following reaction: 3-deoxy-D-manno-octulosonate -2 pyruvate + D-arabinose. Pyruvate was characterized chromatographically and with lactic acid dehydrogenase. D-Arabinose was characterized ch...

Recent single-molecule enzymology measurements with improved statistics have demonstrated that a single enzyme molecule exhibits large temporal fluctuations of the turnover rate constant at a broad range of time scales (from 1 ms to 100 s). The rate constant fluctuations, termed as dynamic disorder, are associated with fluctuations of the protein conformations observed on the same time scales. ...

This article describes an integrated rate equation for the time course of covalent enzyme inhibition under the conditions where the substrate concentration is significantly lower than the corresponding Michaelis constant, for example, in the Omnia assays of epidermal growth factor receptor (EGFR) kinase. The newly described method is applicable to experimental conditions where the enzyme concen...

Two steps of enzymatic oxidations from hypoxanthine to uric acid with xanthine oxidase (XOD) were kinetically analyzed by capillary electrophoresis/dynamic frontal analysis. When a substrate solution was introduced into separation buffer containing XOD, the reaction continuously proceeded during electrophoresis and product resolved zone. A plateau signal detected based on constant rate XOD. The...

Unidirectional influxes of sugars and Na from muscosal solution into the cells of rabbit ileum have been examined. The influxes of glucose, galactose, and 3-0-methyl glucose (3 MG) follow Michaelis-Menten type kinetics and are markedly dependent on the presence ofNa in the mucosal solution. For 3 MG, reduction of Na concentration causes a decrease in maximal rate of influx and little change in ...

vary in a simple way with pH. This variation in maximal initial velocity was interpreted in terms of the ionization constants of two groups in the fumarase-fumarate and fumarase-n-malate complexes. In this article, data are presented for the pH variation of the maximal initial velocities and Michaelis constants of both substrates in 10 mM acetate buffer at 25”. These data may be interpreted in ...

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...