Linked Life Data

488526

Source:http://linkedlifedata.com/resource/pubmed/id/488526

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1979-12-29
pubmed:abstractText
Ecdysone 20-monooxygenase, the enzyme system that hydroxylates ecdysone at C-20 of the side-chain to form ecdysterone, has been characterized in the fat body of early last instar larvae of the tobacco hornworm, Manduca sexta, using a radioenzymological assay. Ecdysterone was demonstrated to be the product of the enzyme system by high-pressure liquid chromatography, gas-liquid chromatography and mass spectrometry. Differential centrifugation, sucrose-gradient centrifugation, electron microscopy and organelle-marker enzyme analysis revealed that ecdysone 20-monooxygenase activity is associated with the mitochondria. The enzymatic properties of ecdysone 20-monooxygenase are that it is most active in a 0.05 M phosphate buffer, is inhibited by Mg2+ and exhibits pH and temperature optima at 7.5 and 30 degrees C, respectively. The enzyme complex has an apparent Km for ecdysone of 1.60 x 10(-7) M and is competitively inhibited by its product, ecdysterone, with an apparent Ki of 2.72 x 10(-5) M. The cytochrome P-450 nature of this insect steroid hydroxylase was initially suggested by its obligate requirement for NADPH and its inhibition by carbon monoxide, p-chloromercuribenzoate, metyrapone and p-aminoglutethimide but not by cyanide. Difference spectroscopy revealed the presence of cytochrome P-450 in the fat-body mitochondrial fraction. A photochemical action spectrum of ecdysone 20-monooxygenase activity confirmed the involvement of cytochrome P-450 in this monooxygenase system.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0303-7207
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
111-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Ecdysone 20-monooxygenase: characterization of an insect cytochrome p-450 dependent steroid hydroxylase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.