Common wisdom holds that ATP hydrolysis is spontaneous because of the weakness of its phosphoanhydride bonds, electrostatic repulsion within the polyanionic ATP[superscript 4]-molecule, and resonance stabilization of the inorganic phosphate and ADP products. By examining the pH-dependence of the hydrolysis Gibbs free energy, we show that in fact,…

Enzyme activators lower K[subscript m] (the Michaelis constant) and/or raise V[subscript max] (the asymptotic reaction velocity at infinite substrate concentration); conversely, inhibitors raise K[Subscript m] and/or lower V[subscript max]. But what if an effector moves both K[subscript m] and V[subscript max] in the same direction? Uncompetitive…

The Hill equation, which models the cooperative ligand-receptor binding equilibrium, turns out to be useful in modeling the progression of infectious disease outbreaks such as CoViD-19. The equation fits well the data for total and daily case numbers, allows tentative predictions for the half-point and end point of the epidemic, and presents a…

In at least two papers published in this "Journal," enzyme free energy diagrams were presented showing enzyme--substrate binding to be nonspontaneous. I present here several different approaches showing that enzyme--substrate binding is "always" spontaneous, and the y-axis of the reaction progress diagrams presented previously…

Living cells are crowded. The presence of so many macromolecules packed into a confined environment affects the structure and function of biological components, and the kinetics and thermodynamics of biochemical reactions. In fact, crowding studies have already led to important biological insights, such as the existence of metabolons and other…

We have developed a laboratory project in which students prepare liposomes, expose them to hyperosmotic and hypoosmotic solutions, and follow the resulting shrinking and swelling (respectively) with laser light scattering. Each light intensity transient can be fit to an exponential decline or rise, with the decay constant (k) and the amplitude…

We have developed a multiweek laboratory project in which students isolate myoglobin and characterize its structure, function, and redox state. The important laboratory techniques covered in this project include size-exclusion chromatography, electrophoresis, spectrophotometric titration, and FTIR spectroscopy. Regarding protein structure,…

A highly instructive, wide-ranging laboratory project in which students study the effects of various parameters on the enzymatic activity of alcohol dehydrogenase has been adapted for the upper-division biochemistry and physical biochemistry laboratory. Our two main goals were to provide enhanced data analysis, featuring nonlinear regression, and…

This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which students assay metal-catalyzed hydrolysis of tRNA[superscript Phe]…

This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which students use fluorescence spectroscopy to study tRNA[superscript…

We have designed a new guided-inquiry laboratory for an advanced biochemistry course. This integrated laboratory focuses on the biomolecule tRNA[superscript Phe] and combines elements of bioorganic and bioinorganic chemistry with biochemistry. Throughout the semester students work together to study tRNA[superscript Phe] structure and ligand…

This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which the thermal unfolding of tRNA[superscript Phe] is studied with…