An innovative theoretical approach that enables the complete characterisation of enzyme– substrate and enzyme–substrate–competitor reactions is generalised to systems with multiple alternative substrates. Based on the quasi-steady-state assumption, time-dependent closed form solutions are presented for cases with even, weak and mixed substrate competition. The analytic framework should facilita...

Suggested Readings: Tabatabai, M. A. 1982. Soil enzymes. p. 903-915, 943-947. In A. L. Page, R. H. Miller, and D. R. Keeney (eds.), Methods of Soil Analysis, Part 2. American Society of Agronomy, Madison, Wisconsin. Dick, W. A. and M. A. Tabatabai. 1992. Significance and potential uses of soil enzymes. p. 95127. In F. Blaine Metting (ed.), Soil Microbial Ecology. Marcel Dekker, New York. Ruggie...

Since Michaelis & Menten (1913) demonstrated that many of the problems encountered by earlier workers in enzyme kinetics could be avoided by measuring initial rates and using kinetic equations in their differential forms, most biochemists have been reluctant to use integrated rate equations. However, confining analysis to the initial linear part of a progress curve wastes much of the available ...

The adaptive fermentation of galactose by yeast is inhibited by fluoride and azide. At sufficiently low concentrations, however, it is stimulated. From a mathematical analysis, using the known fact that fluoride inhibits the enzymes enolase and adenosinetriphosphatase, it is possible to infer the existence of such stimulation. Conditions for this effect are derived which relate the sensitivitie...

Hypoxia inducible factors (HIFs) play vital roles in cellular maintenance of oxygen homeostasis. These transcription factors are responsible for the expression of genes involved in angiogenesis, metabolism, and cell proliferation. Here, we generate a detailed mathematical model for the enzyme kinetics of α-ketoglutarate-dependent HIF prolyl 4-hydroxylase domain (PHD) dioxygenases to simulate ou...

Serial crystallography at a synchrotron has been used to obtain time-resolved atomic resolution density maps of enzyme catalysis in copper nitrite reductase. Similar XFEL studies, intended to out-run radiation damage, will also soon appear.

Fluorescent spectroscopy experiments with single-enzyme molecules yield a large volume of statistical data that can be analyzed and interpreted using stochastic models of enzyme action. Here, we present two models, each based on the mechanism that an enzyme molecule must pass through a sequence of conformational transformations to complete its catalytic turnover cycle. In the simplest model, on...