Isotope effects are one of the most powerful kinetic tools for determining enzyme mechanisms. There are three methods of measurement. First, one can compare reciprocal plots with labeled and unlabeled substrates. The ratio of the slopes is the isotope effect on V/K, and the ratio of the vertical intercepts is the isotope effect on V(max). This is the only way to determine V(max) isotope effects...

Human intrinsic factor has been isolated from gastric juice. The protein was purified 853-fold with a yield of 85 % utilizing affinity chromatography on vitamin Blz-Sepharose as the sole purification technique. The final preparation was homogeneous based on polyacrylamide gel electrophoresis and sedimentation equilibrium ultracentrifugation. The isolated protein (20 pg) corrected vitamin Blz ma...

Adsorbed molecules are involved in many reactions on solid surface that are of great technological importance. As such, there has been tremendous effort worldwide to learn how to predict reaction rates and equilibrium constants for reactions involving adsorbed molecules. Theoretical calculation of both the rate and equilibrium constants for such reactions requires knowing the entropy and enthal...

In this paper a new method for Euclidean reconstruction from sequences of images taken by uncalibrated cameras, with constant intrinsic parameters, is described. Our approach leads to a variant of the so called Kruppa equations. It is shown that it is possible to calculate the intrinsic parameters as well as the Euclidean reconstruction from at least three images. The novelty of our approach is...

microalgal growth curve, after the exponential phase, shows a stationary phase where algalbiomass production is inhibited and remains constant by some factors such as nutrientdepletion and intrinsic behavior. the present study is concerned with evaluating effects ofthe culture medium condition and intrinsic behavior on biomass production by dunaliellatertiolecta. to this end, effect of ph, nutr...

Nicotinic acetylcholine receptor (AChR) channels at neuromuscular synapses rarely open in the absence of agonists, but many different mutations increase the unliganded gating equilibrium constant (E0) to generate AChRs that are active constitutively. We measured E0 for two different sets of mutant combinations and by extrapolation estimated E0 for wild-type AChRs. The estimates were 7.6 and 7.8...

We characterized the reversible folding-unfolding transition of Bacillus subtilis exocellular chitosanase from either thermal or urea denaturation of the protein. The transitions were monitored in each case by intrinsic fluorescence changes and resistance to proteolysis. Unfolding and refolding kinetics and differential scanning calorimetry analysis suggested a two-state equilibrium. The equili...

To determine whether the molecular configuration of vitamin B(12) influences the attachment of intrinsic factor-vitamin B(12) complex to ileal microvillous membrane receptor sites, we have examined the kinetics of uptake of intrinsic factor-bound cyanocobalamin by brush borders and microvillous membranes isolated from guinea pig ileum, and have compared this uptake with that of intrinsic factor...