Related Experiment Video
Updated: Jun 19, 2026

Measuring Enzymatic Stability by Isothermal Titration Calorimetry
Published on: March 26, 2019
SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. II
1Department of Chemistry, Columbia University, New York.
Abstract:
1. The pH-activity relationship of invertase has been studied in vivo and in vitro under identical external environmental conditions. 2. The effect of changing (H(+)) upon the sucroclastic activity of living cells of S. cerevisiae and of invertase solutions obtained therefrom has been found, within experimental error, to be identical. 3. The region of living yeast cells in which invertase exerts its physiological activity changes its pH freely and to the same extent as that of the suspending medium. It is suggested that this may indicate that this intracellular enzyme may perform its work somewhere in the outer region of the cell. 4. In using live cells containing maltase, no evidence of increased sucroclastic activity around pH 6.9, due to the action of Weidenhagen's alpha-glucosidase (maltase), was found.
Related Concept Videos
Introduction to Enzyme Kinetics
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
Enzyme Kinetics
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Equivalence: In Vitro and In Vivo Bioequivalence
Enzyme Inhibition
Drug Product Performance: In Vitro–In Vivo Correlation
Turnover Number and Catalytic Efficiency
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion. The...

