Related Experiment Video
Updated: Jul 18, 2026
11:27
X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
An effective metallohydrolase model with a supramolecular environment: structures, properties, and activities
Ying-Hua Zhou1, Heng Fu, Wei-Xi Zhao
1MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (People's Republic of China).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|December 14, 2006
Summary
This study synthesized a zinc-beta-cyclodextrin complex for ester hydrolysis. The complex showed potent catalytic activity, outperforming other zinc species in ester breakdown.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Catalysis
Background:
- Supramolecular inclusion complexes offer unique environments for chemical reactions.
- Zinc(II) complexes are known catalysts for ester hydrolysis.
- Beta-cyclodextrin (beta-CD) can enhance the reactivity and selectivity of guest molecules.
Purpose of the Study:
- To synthesize and characterize a novel supramolecular inclusion complex of zinc(II) with a diethylenetriamine ligand and beta-cyclodextrin.
- To investigate the catalytic activity of the synthesized complex in ester hydrolysis.
- To determine the kinetic parameters and compare its efficacy with other zinc species.
Main Methods:
- Synthesis and structural characterization of the supramolecular complex [Zn(L1)(H2O)2(beta-CD)](ClO4)2.9.5 H2O.
- Isolation and characterization of the active catalytic species [Zn(L1)(H2O)(OH)(beta-CD)](ClO4).
- Kinetic studies of p-nitrophenyl acetate hydrolysis catalyzed by the complex under varying pH and substrate concentrations.
Main Results:
- The apparent inclusion stability constant was determined to be (5.91±0.03)x10^3.
- The pKa values of coordinated water molecules were measured as 8.20±0.08 and 10.44±0.08.
- The complex exhibited potent catalytic activity in ester hydrolysis, with the [Zn(L1)(OH)2(beta-CD)] species showing particularly high second-order rate constants (24.0 M⁻¹s⁻¹).
Conclusions:
- The synthesized zinc-beta-cyclodextrin complex is an effective catalyst for ester hydrolysis.
- The catalytic efficiency is attributed to the unique supramolecular environment and the properties of the zinc center.
- This system represents a promising advancement in the development of highly active and selective metal-based catalysts.
Related Concept Videos
02:34Enzymes
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
01:13Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
01:07Catalytically Perfect Enzymes
The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at high-speed. Their catalytic efficiency values range from 108-109 M-1s-1. These enzymes are also called 'diffusion-controlled' as the only rate-limiting step in the catalysis is that of the substrate diffusion into the active site. Examples include triose phosphate isomerase, fumarase, and superoxide dismutase.
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
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,...
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,...
00:49Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...