Related Experiment Video
Updated: Oct 4, 2026

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Zinc-mediated thermal stabilization of carboxypeptidase A
1Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Tel-Aviv, Israel.
Abstract:
In this study we investigated the contribution of Zn ions to the catalytic and structural thermostability of carboxypeptidase A (CPA). Structural studies on CPA molecule, performed in the presence of a number of ligands, demonstrated the multiple binding models around Zn ions which may affect the enzyme functions. Zinc was reported to bind at various sites in the CPA molecule at room temperature leading to inhibition of its enzymic activity. In this study we found that binding of Zn to CPA molecule followed by exposure to 50 degrees C did not inhibit the enzymic activity but activates and protects it against heat denaturation. The stabilization effect was found to be dependent on the increasing Zn/CPA ratios. The moderate changes of CPA activity as well as the UV and fluorescence spectra analyses indicate that the main function of the newly introduced zinc atoms is structural rather than catalytical.
Related Concept Videos
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Protein Denaturation
Diversity of Archaea IV
Introduction to Mechanisms of Enzyme Catalysis
Diversity of Archaea III
Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...

