I. Studies in the Chemistry of Sodium Dithionite. II. A pH Study of the alpha-Chymotrypsin Catalysed Hydrolysis of Methyl Hippurate

Citation

Gordon, Thomas Pascoe (1959) I. Studies in the Chemistry of Sodium Dithionite. II. A pH Study of the alpha-Chymotrypsin Catalysed Hydrolysis of Methyl Hippurate. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/JPWX-NF92. https://resolver.caltech.edu/CaltechETD:etd-02012006-154755

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Part I. The kinetics of the air oxidation of sodium dithionite in alkaline solution suggest the transfer of an electron from [...] radical-ions, which are in equilibrium with [...] ions, to molecular oxygen in the rate determining step. Electron paramagnetic resonance experiments confirm the presence of [...] radical-ions in equilibrium with [...] ions in solution. Electrolytic reduction of sulfurous acid solutions at constant potential in the range -0.7v to -0.9v produces dithionite at constant current efficiency. Thermal decomposition of dithionite solutions occurs slowly at first, apparently by a free radical mechanism, and then rapidly, indicating a degenerate chain-branching mechanism. Part II. The results of a pH study of the [alpha]-chymotrypsin catalysed hydrolysis of methyl hippurate at three different added salt concentrations are consistent with the postulation of ionizing groups at the active site of the enzyme with [...] values 6.9 +/- 0.1 and 8.6 +/- 0.1. Important interactions of added salt and hydrogen ion concentrations are not indicated. Hippuric acid and L-tryptophan are shown to be competitive inhibitors. The development of a negative charge at or near the active site of the enzyme above pH 8 is confirmed.

Thesis Files