User:Mikirehil/sandbox
| polyneuridine-aldehyde esterase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Polyneuridine-Aldehyde Esterase 3D Rendering | |||||||||
| Identifiers | |||||||||
| EC no. | 3.1.1.78 | ||||||||
| CAS no. | 87041-55-2 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
In enzymology, a polyneuridine-aldehyde esterase (EC 3.1.1.78) is an enzyme that catalyzes the chemical reaction:
- polyneuridine aldehyde + H2O 16-epivellosimine + CO2 + methanol
Thus, the two substrates of this enzyme are polyneuridine aldehyde and H2O, whereas its three products are 16-epivellosimine, CO2, and methanol.[1]
This enzyme participates in indole and ipecac alkaloid biosynthesis.
Nomenclature[edit]
This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is polyneuridine aldehyde hydrolase (decarboxylating). Other names in common use include:
- polyneuridine aldehyde esterase
- PNAE
Homologues[edit]
This enzyme is found in various forms in plant species such as Arabidopsis thaliana, Glycine max (soybean), Vitis vinifera (wine grape), and Solanum lycopersicum (tomato) among others.
Polyneuridine-aldehyde esterase also appears in select bacteria including Enterobacter cloacae.
Structure[edit]
The secondary structure of this enzyme consists mainly of alpha helices. In its native form, this enzyme has a tertiary structure that includes two main lobes (as depicted above in the blue 3D representation on the top right).
Reaction[edit]
Polyneuridine-aldehyde esterase catalyzes the hydrolysis of the molecule polyneuridine-aldehyde (in the presence of water), removing a methanol from the polyneuridine-aldehyde molecule.This hydrolysis is illustrated in the first step of the reaction diagram (pictured left). The hydrolyzed compound is polyneuridine β-aldehydoacid, the second molecule shown in the reaction diagram at left, which is an intermediate compound in this reaction. The carboxylic acid group is quickly removed as this compound spontaneously decarboxylates, yielding 16-epivellosimine and carbon dioxide.[1]
Mechanism[edit]
The mechanism of hydrolysis performed by polyneuridine-aldehyde esterase is not known. It has been suggested that the enzyme utilizes a catalytic triad composed of Ser-87, Asp-216 and His-244.[3] The catalytic amino acid order is the same as the order of enzymes that are part of the α/β hydrolase family. Thus polyneuridine-aldehyde esterase may be a novel member of the α/β hydrolase group.[4]
Broader Significance[edit]
This enzyme is a part of the pathway of indole alkaloid biosynthesis. The indole alkaloids that result from this metabolic pathway are used by many plant species as a defense against herbivores and parasites.
Open Questions[edit]
The precise mechanisms by which this enzyme performs its function is still unknown. As noted above, researchers are formulating suggestions as to how polyneuridine-aldehyde esterase catalyses the decomposition of polyneuridine-aldehyde, but a mechanism has not yet been affirmed with absolute certainty. Due to the lack of complete understanding of polyneuridine-aldehyde esterase's precise mechanism, this enzyme cannot be grouped into a family of enzymes. Based on mechanism theories, suggestions can be made as to how this enzyme should be categorized, and some parallels can be drawn between polyneuridine-aldehyde esterase and other enzymes.
References[edit]
- ^ a b Pfitzner A, Stöckigt J (August 1983). "Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloids". Planta Med. 48 (8): 221–7. doi:10.1055/s-2007-969924. PMID 17404987.
{{cite journal}}: CS1 maint: date and year (link) - ^ PDB: 3GZJ; Yang L, Hill M, Wang M, Panjikar S, Stöckigt J (2009). "Structural basis and enzymatic mechanism of the biosynthesis of C9- from C10-monoterpenoid indole alkaloids". Angew. Chem. Int. Ed. Engl. 48 (28): 5211–3. doi:10.1002/anie.200900150. PMID 19496101.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Mattern-Dogru E, Ma X, Hartmann J, Decker H, Stöckigt J (June 2002). "Potential active-site residues in polyneuridine aldehyde esterase, a central enzyme of indole alkaloid biosynthesis, by modelling and site-directed mutagenesis". Eur. J. Biochem. 269 (12): 2889–96. doi:10.1046/j.1432-1033.2002.02956.x. PMID 12071952.
{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link) - ^ Dogru E, Warzecha H, Seibel F, Haebel S, Lottspeich F, Stöckigt J (March 2000). "The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/betahydrolase super family". Eur. J. Biochem. 267 (5): 1397–406. doi:10.1046/j.1432-1327.2000.01136.x. PMID 10691977.
{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
Further reading[edit]
- Pfitzner A and Stockigt J (1983). "Polyneuridine aldehyde esterase: an unusual specific enzyme involved in the biosynthesis of sarpagine type alkaloids". J. Chem. Soc. Chem. Commun. (8): 459–460. doi:10.1039/C39830000459.
Category:EC 3.1.1 Category:Enzymes of unknown structure
 | This hydrolase article is a stub. You can help Wikipedia by expanding it. |