Juvenile-hormone esterase
| juvenile hormone esterase | |||||||||
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| Identifiers | |||||||||
| EC number | 3.1.1.59 | ||||||||
| CAS number | 50812-15-2 | ||||||||
| 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 / EGO | ||||||||
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| Search | |
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| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
In enzymology, juvenile hormone esterase (JH esterase) is an enzyme that catalyzes the hydrolysis of juvenile hormone. For example, the juvenile hormone II (found in Lepidoptera):
This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is methyl-(2E,6E)-(10R,11S)-10,11-epoxy-3,7,11-trimethyltrideca-2,6-dienoate acylhydrolase. Other names in common use include JH esterase, juvenile hormone esterase, and juvenile hormone carboxyesterase.
Juvenile hormone (JH) controls insect metamorphosis . High JH titers maintain the larval state while a decrease in the JH titer initiates the pupation sequence as well as a change in tissue commitment away from synthesis of larval tissues to pupal tissues at the pupal stage . The drop in JH titer at the beginning of the last larval instar in the Lepidoptera appears to be due to a combination of increased metabolism and decreased synthesis. In the Lepidoptera, JH is initially metabolized by ester hydrolysis; esterases capable of hydrolyzing JH are detectable in the hemolymph at times during the last larval instar that appear to coincide with reported drops in the JH titre. The JHE's are also selective for the 2E methyl ester of the naturally occurring JH's. These studies suggest that the JHE's may be important in the regulation of the JH titre and therefore involved in the initiation of and the commitment to the pupal stage. JHE's appear to be produced by the fat body and this production can be stimulated by exogenous JH in Hyalophora pupae, a stage devoid of JHE activity. Stimulation of JHE activity by JH has also been noted recently in adults of Leptinotarsa decemlineata and pupae of Galleria mellonella. However, to date, no reported studies have examined this phenomenon during the last larval instar when these enzymes are thought to be of primary importance. Thus this laboratory undertook an investigation of the hemolymph JHE regulation during the last larval instar of the cabbage looper, Trichoplusia ni.
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