World Library  
Flag as Inappropriate
Email this Article

Aminocyclopropanecarboxylate oxidase

Article Id: WHEBN0014044909
Reproduction Date:

Title: Aminocyclopropanecarboxylate oxidase  
Author: World Heritage Encyclopedia
Language: English
Subject: Ethylene, List of EC numbers (EC 1)
Collection: Ec 1.14.17, Enzymes of Known Structure
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Aminocyclopropanecarboxylate oxidase

Aminocyclopropanecarboxylate oxidase
Identifiers
EC number 1.14.17.4
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

In enzymology, an aminocyclopropanecarboxylate oxidase (EC 1.14.17.4) is an enzyme that catalyzes the chemical reaction

1-aminocyclopropane-1-carboxylate + ascorbate + O2 \rightleftharpoons ethylene + cyanide + dehydroascorbate + CO2 + 2 H2O

The 3 substrates of this enzyme are 1-aminocyclopropane-1-carboxylate, ascorbate, and O2, whereas its 5 products are ethylene, cyanide, dehydroascorbate, CO2, and H2O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with reduced ascorbate as one donor, and incorporation of one ato of oxygen into the other donor. The systematic name of this enzyme class is 1-aminocyclopropane-1-carboxylate oxygenase (ethylene-forming). Other names in common use include ACC oxidase, and ethylene-forming enzyme.

Structural studies

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1W9Y and 1WA6.

Reaction Mechanism

Mechanistic and structural studies support binding of ACC and oxygen to an iron center located in the active site of ACC oxidase. The ring-opening of bound ACC is believed to result in the elimination of ethylene together with an unstable intermediate, cyanoformate ion, which then decomposes to cyanide ion and carbon dioxide. Cyanide ion is a known deactivating agent for iron-containing enzymes, but the cyanoformate ion intermediate is believed to play a vital role to carry potentially toxic cyanide away from the active site of ACC oxidase. Cyanoformate was recently identified in condensed media as a tetraphenylphosphonium salt with a weak carbon-carbon bond.

References

  • Zhang Z, Schofield CJ, Baldwin JE, Thomas P, John P (Pt 1). "Expression, purification and characterization of 1-aminocyclopropane-1-carboxylate oxidase from tomato in Escherichia coli". Biochem. J. 307 (Pt 1): 77–85.  
  • Zhang Z, Barlow JN, Baldwin JE, Schofield CJ (1997). "Metal-catalyzed oxidation and mutagenesis studies on the iron(II) binding site of 1-aminocyclopropane-1-carboxylate oxidase". Biochemistry. 36 (50): 15999–6007.  
  • Pirrung MC (1999). "Ethylene biosynthesis from 1-aminocyclopropanecarboxylic acid". Acc. Chem. Res. 32: 711–718.  
  • Charng YY, Chou SJ, Jiaang WT, Chen ST, Yang SF (2001). "The catalytic mechanism of 1-aminocyclopropane-1-carboxylic acid oxidase". Arch. Biochem. Biophys. 385 (1): 179–85.  
  • Thrower JS, Blalock R 3rd Klinman JP (2001). "Steady-state kinetics of substrate binding and iron release in tomato ACC oxidase". Biochemistry. 40 (32): 9717–24.  
  • Pirrung MC, Kaiser LM, Chen J (July 1993). "Purification and properties of the apple fruit ethylene-forming enzyme". Biochemistry 32 (29): 7445–50.  
  • Murphy LJ, Robertson KN, Harroun SG, Brosseau CL, Werner-Zwanziger U, Moilanen J, Tuononen HM, Clyburne JA (2014). "A simple complex on the verge of breakdown: isolation of the elusive cyanoformate ion". Science 344 (6179): 75–8.  
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.