Thermodynamics of fatty acid degradation.

In this communication, the correlation of some thermodynamic properties of structurally similar biological compounds with items such as the number of carbon atoms or the number of its characteristic groups, such as phosphates, was applied to enzyme thermodynamics, to advance the thermodynamics of fatty acid degradation. It was shown that these concepts apply equally well for all three major thermodynamic functions: Gibbs energy of formation, enthalpy of formation, and entropy of formation. First, the standard transformed Gibbs energies of formation, Δ(f)G'(o), were calculated for the major portion of saturated fatty acids at 25 °C and pH 5, pH 7, and pH 9.

Optimization of conditions for acid protease partitioning and purification in aqueous two-phase systems using response surface methodology.

Aspergillopepsin I, an acid protease, was purified using an aqueous two-phase system that comprised various combinations of polyethylene glycol (PEG), NaH2PO4 and NaCl. Partition of the enzyme depended upon the molecular mass of the PEG and the presence of NaCl. With PEG 1500, 4000 and 6000, the partition coefficients were increased by 1,500-, 1,800- and 560-fold compared to values without NaCl.

Deriving the rate equations for product inhibition patterns in bisubstrate enzyme reactions.

In this work, the full rate equations for 17 completely reversible bisubstrate enzyme kinetic mechanisms, with two substrates in the forward and two in the reverse direction, have been presented; among these are rapid equilibrium, steady-state, and mixed steady-state and rapid equilibrium mechanisms. From each rate equation eight product inhibition equations were derived, four for the forward and four for the reverse direction. All the corresponding product inhibition equations were derived in full; thus a total of 17 x 8 = 136 equations, were presented.

Inactivation of cytochrome-c with glucose oxidase.

A novel reaction of cytochrome-c from the horse heart with the enzyme glucose oxidase from Aspergillus niger (EC 1.1.3.

The chemical mechanism of action of glucose oxidase from Aspergillus niger.

Glucose oxidase from Aspergillus niger (EC 1.1.3.

A general method for the analysis of random bisubstrate enzyme mechanisms.

In the present communication, a general method for the kinetic analysis of random bisubstrate mechanisms is described. The method comprises a stepwise application of the following kinetic and ligand-binding experiments: determination of steady-state kinetic constants, product inhibition patterns, maximum rate relationships, application of alternate substrates, application of dead-end inhibitors, direct binding of substrates, kinetic isotope effects, and isotope exchange studies. This general method was applied to a practical example: a yeast alcohol dehydrogenase-catalyzed oxidation of 2-propanol by NAD(+) at pH 7.

The three zinc-containing alcohol dehydrogenases from baker's yeast, Saccharomyces cerevisiae.

This review is a summary of our current knowledge of the structure, function and mechanism of action of the three zinc-containing alcohol dehydrogenases, YADH-1, YADH-2 and YADH-3, in baker's yeast, Saccharomyces cerevisiae. The opening section deals with the substrate specificity of the enzymes, covering the steady-state kinetic data for its most known substrates. In the following sections, the kinetic mechanism for this enzyme is reported, along with the values of all rate constants in the mechanism.