47 by: Tasneem Idris
Student – Tasneem Idris
Enzyme – Maleate Isomerase
EC # – 5.2.11
Maleate isomerase is predominantly found in various bacterial species, such as Pseudomonas and Escherichia coli. These bacteria often inhabit soil, water, or environments rich in organic compounds, where the enzyme contributes to the catabolism of certain aromatic compounds. The presence of maleate isomerase allows these microorganisms to utilize maleate as a carbon and energy source, aiding in the degradation of potentially toxic substances. Maleate isomerase catalyzes the reversible isomerization of maleate to fumarate, converting a cis isomer into its trans form. This reaction is a key step in metabolic pathways that break down aromatic compounds and other related molecules, ultimately feeding into the
tricarboxylic acid (TCA) cycle for energy production. The enzyme enables bacteria to metabolize aromatic compounds such as benzoate or phthalate, which are broken down into
maleate and then further processed through fumarate. Maleate isomerase plays an important role in bioremediation, as it helps bacteria degrade pollutants such as polycyclic aromatic hydrocarbons (PAHs) and other aromatic substances commonly found in contaminated soil and water. The enzyme belongs to the Asp/Glu racemase superfamily, characterized by a co served structural motif in the active site and shared catalytic mechanisms involving carboxylate containing substrates. While most members of the superfamily utilize cysteine residues as acids or bases, maleate isomerase distinguishes itself by forming a covalent intermediate with the substrate, highlighting the catalytic versatility within the enzyme family.
This enzyme showcases the adaptability of bacteria in utilizing various organic compounds and illustrates nature’s capacity for chemical transformation, even with structurally similar molecules like geometric isomers.
References
Maleate cis-trans isomerase from Arthrobacter sp.. TPU 5446. Journal of Fermentation and Bioengineering. https://www.sciencedirect.com/science/article/pii/0922338X96877415
Information on EC 5.2.1.1 – maleate isomerase. Information on EC 5.2.1.1 – maleate isomerase – BRENDA Enzyme Database. (n.d.). https://www.brendaenzymes.
org/enzyme.php?ecno=5.2.1.1
JW;, D. H. B. (n.d.). Computational investigations on the catalytic mechanism of maleate isomerase: The role of the active site cysteine residues. Physical chemistry chemical physics : PCCP. https://pubmed.ncbi.nlm.nih.gov/24827730/
Maleate isomerase. maleate isomerase(EC 5.2.1.1) – Creative Enzymes. (n.d.). https://www.creative-enzymes.com/product/maleate-isomerase_15610.html
Takamura, Y., Ozawa, H., & Soejima, M. (1970, October 1). Studies on the induced synthesis of maleate cis-trans isomerase by Malonate: Part IV. catabolite repression and its reversal of maleate cis-trans isomerase. OUP Academic. https://academic.oup.com/bbb/article/34/10/1501/5978187
