A comparison of the effects of fluoride and chloride ions upon the activity of yeast alcohol dehydrogenase

• Main Author: Hannan, Ellen J.
• Format: Others
• Published: PDXScholar 1969
• Subjects: Dehydrogenase
• Online Access: https://pdxscholar.library.pdx.edu/open_access_etds/458; https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1457&context=open_access_etds

Very little is known about the effect of hydrofluoric acid and of the fluoride ion on enzyme systems. The purpose of this work was to determine the effect of hydrofluoric acid and of the fluoride ion on the enzyme, yeast alcohol dehydrogenase and to distinguish between the effect of the fluoride ion and of hydrofluoric acid. The rate of the enzyme reaction was followed spectrophotometrically at 340 mμ on the Cary 14 Model spectrophotometer according to the method of Racker. The data taken from the instrument recordings were plotted on two types of graphs, the Lineweaver-Burk plot and the Hanes plot. Conclusions were drawn from the calculations made on these plots. Inhibition studies were run using KCI, NaCl, KF and NaF varying in concentration from 0.001 to 0.12 M at two different pH levels. For the fluoride salts, this gave a concentration of HF which varied from 8.94 x 10ˉ⁸ to 1.07 x 10ˉ⁵ M at pH 7.5 and 8.94 x 10ˉ̄⁹ to 1.07 x 10˜⁶ M at pH 8.5 The fluoride salts showed no greater inhibition than the chloride salts at either pH. Since there is no difference in inhibition between the two types of salts, the inhibition cannot be attributed to the presence of hydrofluoric acid. If the inhibition had been due to hydrofluoric acid, we would have observed a greater inhibition with the fluoride salts than with the chloride salts since hydrochloric acid is 100% ionized.