+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Microsomal delta 8,14-sterol delta 14-reductase in higher plants. Characterization and inhibition by analogues of a presumptive carbocationic intermediate of the reduction reaction



Microsomal delta 8,14-sterol delta 14-reductase in higher plants. Characterization and inhibition by analogues of a presumptive carbocationic intermediate of the reduction reaction



European Journal of Biochemistry 185(3): 605-614



An enzymatic assay for delta 8,14-sterol delta 14-reductase, an enzyme involved in sterol biosynthesis, has been developed for the first time in higher plants. The properties of the microsomal enzyme have been established with respect to cofactor requirements, kinetics and substrate specificity. This enzymatic double-bound reduction is thought to proceed through an electrophilic addition mechanism, involving a C14 putative carbonium ion high-energy intermediate. Using this in vitro assay, ammonium and iminium analogues of this cationic intermediate were shown to be potent inhibitors of the reduction reaction. Thus, compounds of the N-alkyl-8-aza-4 alpha,10-dimethyl-trans-decal-3 beta-ol series strongly inhibited sterol reductase (I50 = 0.07 - 4 microM) (I50/Km = 10(-4) - 10(-3), as did the antimycotic agent 15-azasterol (I50 = 0.03 microM); all of these compounds act as reaction-intermediate analogues of the proposed C14 carbonium ion intermediate. Moreover, the in vitro inhibition of the plant sterol reductase by a series of ammonium-ion-containing fungicides was demonstrated. The relative specificity of these different series of inhibitors toward cycloeucalenol-obtusifoliol isomerase, delta 8----delta 7-sterol isomerase and delta 8,14-sterol delta 14-reductase, was directly studied.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 040700566

Download citation: RISBibTeXText

PMID: 2591378


Related references

Microsomal Δ8,14-sterol Δ14-reductase in higher plants : Characterization and inhibition by analogues of a presumptive carbocationic intermediate of the reduction reaction. Febs Journal 185(3): 605-614, 1989

Sterol biosynthesis: strong inhibition of maize delta 5,7-sterol delta 7-reductase by novel 6-aza-B-homosteroids and other analogs of a presumptive carbocationic intermediate of the reduction reaction. Biochemistry 35(22): 7069-7076, 1996

Phytosterol biosynthesis Enzymatic characterization and potent inhibition of maize DELTA-5,7-sterol DELTA-7-reductase by novel azasteroids analogs of a carbocationic intermediate of the reduction reaction. FASEB Journal 11(9): A900, 1997

Sterol biosynthesis: strong inhibition of maize D5,7-sterol D7-reductase by novel 6-aza-B-homosteroids and other analogs of a presumptive carbocationic intermediate of the reduction reaction. Biochemistry (American Chemical Society) 35: 69-76, 1996

Inhibition of delta 8 delta 7 sterol isomerase and of cycloeucalenol obtusifoliol isomerase by n benzyl 8 aza 4 alpha 10 dimethyl trans decal 3 beta ol an analog of the carbocationic high energy intermediate. Phytochemistry 24(6): 1223-1232, 1985

Inhibition of delta 8 leads to delta 7-sterol isomerase and of cycloeucalenol-obtusifoliol isomerase by N-benzyl-8-aza-4 alpha,10-dimethyl-trans-decal-3 beta-ol, an analogue of a carbocationic high energy intermediate. Phytochemistry 4(6): 1223-1232, 1985

Inhibition of sterol biosynthesis in higher plants by analogues of high energy carbocationic intermediates. Kuhn, P J , Et Al (Ed ) Biochemistry Of Cell Walls And Membranes in Fungi Xiii+327p Springer-Verlag New York, Inc : Secaucus, New Jersey, Usa; Berlin, West Germany Illus 205-222, 1990

Azasterol inhibitors in yeast. Inhibition of the delta 24-sterol methyltransferase and the 24-methylene sterol delta 24(28)-reductase in sterol mutants of Saccharomyces cerevisiae. Canadian Journal of Biochemistry 57(3): 201-208, 1979

Inhibition of the sterol delta 14-reductase and delta 8 leads to delta 7-isomerase in fungi. Transactions Biochemical Society 18(1): 59-61, 1990

Inhibition of sterol delta 8 delta 7 isomerase and delta 14 reductase by fenpropimorph tridemorph and fenpropidin in cell free enzyme systems from saccharomyces cerevisiae. Phytochemistry 26(3): 663-668, 1987

Inhibition of the sterol Delta 14-reductase and Delta 8-> Delta 7-isomerase in fungi. Biochemical Society Transactions 18(1): 59-61, 1990

Identification of delta 5,7-sterol-delta 7-reductase in higher plant microsomes. Biochemical and Biophysical Research Communications 181(1): 465-473, 1991

Delta 7 sterol delta 5 dehydrogenase and delta 5 7 sterol delta 7 reductase of rat liver. Clayton, Raymond B (Edited By) Methods in Enzymology Vol Xv Steroids And Terpenoids Xvii + 903p Illus Academic Press Inc : New York, N Y , U S A ; London, England 501-514, 1969

Phytosterol synthesis, identification, enzymatic characterization and design of potent mechanism-based inhibitors of delta 5,7-sterol-delta 7-reductase. Physiology biochemistry and molecular biology of plant lipids 188, 1997

Novel inhibitors of sterol C-14 demethylase and DELTA-14 reductase/DELTA-8 fwdarw -DELTA-7 isomerase for cereal disease control. Pesticide Science 35(4): 339-347, 1992