Document type
ArticleVersion
Accepted versionPublication date
All rights reserved
Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/108975
Effect of crowding by dextrans on the hydrolysis of N-Succinyl-L-phenyl-Ala-p-nitroanilide catalyzed by α-chymotrypsin
Journal Title
Director/Tutor
Journal ISSN
Volume Title
Related resource
Abstract
Traditionally, studies on the diffusion-controlled reaction of biological macromolecules have been carried out in dilute solutions (in vitro). However, in an intracellular environment (in vivo), there is a high concentration of macromolecules, which results in nonspecific interactions (macromolecular crowding). This affects the kinetics and thermodynamics of the reactions that occur in these systems. In this paper, we study the crowding effect of large macromolecules on the reaction rates of the hydrolysis of N-succinyl-L-phenyl-Ala-p-nitroanilide catalyzed by R-chymo- trypsin, by adding dextrans of various molecular weights to the reaction solutions. The results indicate that the volume occupied by the crowding agent, but not its size, plays an important role in the rate of this reaction. A vmax decay and a Km increase were obtained when the dextran concentration in the sample was increased. The increase in Km can be attributed to the slowing of protein diffusion, due to the presence of crowding. Whereas the decrease in vmax could be explained by the effect of mixed inhibition by product, which is enhanced in crowded media. As far as we know, this is the first reported experiment on the crowding effect in an enzymatic reaction with a mixed inhibition by product.
Subject
Subject (English)
Citation
Citation
PASTOR, Isabel, et al. Effect of crowding by dextrans on the hydrolysis of N-Succinyl-L-phenyl-Ala-p-nitroanilide catalyzed by α-chymotrypsin. Journal of Physical Chemistry B. 2011. Vol. 115, num. 5, pags. 1115-1121. ISSN 1520-6106. [consulted: 17 of June of 2026]. Available at: https://hdl.handle.net/2445/108975