Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
COMPARISON OF AN ESTERASE ASSOCIATED WITH ORGANOPHOSPHATE RESISTANCE IN LUCILIA-CUPRINA WITH AN ORTHOLOGUE NOT ASSOCIATED WITH RESISTANCE IN DROSOPHILA-MELANOGASTER
Autore:
PARKER AG; CAMPBELL PM; SPACKMAN ME; RUSSELL RJ; OAKESHOTT JG;
Indirizzi:
CSIRO,DIV ENTOMOL,POB 1700 CANBERRA ACT 2601 AUSTRALIA CSIRO,DIV ENTOMOL CANBERRA ACT 2601 AUSTRALIA AUSTRALIAN NATL UNIV,DEPT BOT & ZOOL CANBERRA ACT 2601 AUSTRALIA
Titolo Testata:
Pesticide biochemistry and physiology
fascicolo: 2, volume: 55, anno: 1996,
pagine: 85 - 99
SICI:
0048-3575(1996)55:2<85:COAEAW>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACETYLCHOLINESTERASE; INSECTICIDES; ALLOZYMES; PROTEINS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
A.G. Parker et al., "COMPARISON OF AN ESTERASE ASSOCIATED WITH ORGANOPHOSPHATE RESISTANCE IN LUCILIA-CUPRINA WITH AN ORTHOLOGUE NOT ASSOCIATED WITH RESISTANCE IN DROSOPHILA-MELANOGASTER", Pesticide biochemistry and physiology, 55(2), 1996, pp. 85-99

Abstract

Orthologous E3 and EST23 carboxylesterases have been enriched over 200-fold from organophosphate (OF) susceptible strains of Lucilia cuprina and Drosophila melanogaster, respectively. Mutants of E3 are associated with OP resistance but no resistance mutations of EST23 are known. The behaviours of the two enzymes were very similar during purification which involved differential centrifugation followed by three or four ion exchange and gel filtration chromatographic steps. Nondenaturingpolyacrylamide gel electrophoresis and histochemical staining for esterase activity revealed no other esterases in the enriched material. Two-dimensional polyacrylamide gel electrophoresis (native followed by denaturing) showed that a major 70-kDa component of each preparation comigrates with E3 and EST23 activities, respectively. Kinetic properties of the enzymes are also very similar. Estimates of K-m, K-cat, and K-cat/K-m for alpha-naphthyl acetate are 42 +/- 18 mu M, 19 sec(-1), and 4.6 x 10(5) M(-1) sec(-1), respectively, for E3, and 62 +/- 25 mu M, 23 sec(-1), and 3.7 x 10(5) M(-1) sec(-1), for EST23. Both enzymes are potently inhibited by dibrom and less potently by another OF, diisopropylflurophosphate. E3 is also potently inhibited by paraoxon, whereas EST23 is at least 8-fold less susceptible to inhibition by paraoxon. This supports previous analyses of crude homogenates which showed that E3 is more susceptible to inhibition by paraoxon and fenitrooxon than is EST23 or the target site fbr OP action, acetylcholinesterase. Itis proposed that the unusual affinity of E3 for such OPs is a necessary precondition for mutations that enable it to confer OP resistance on L. cuprina. (C) 1996 Academic Press, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 15:41:14