title: Determination of aconitate isomerase in plants.
abstract: We have developed a method for measuring aconitate isomerase (EC 5.3.3.7) in plants which depends on the release of tritium from labeled trans-aconitate. The released tritium is separated from labeled aconitate by passage through a column of strong anion-exchange resin. This method is more sensitive, simpler, and more specific than previous methods, especially with crude extracts. The validity of the method was demonstrated by a comparison of the quantity of tritium released with the amount of cis-aconitate isomerized and this comparison demonstrated an isotope effect. Aconitase did not interfere. The method was tested by measuring aconitate isomerase in crude extracts of several higher plant species and tissues and these analyses showed that wheat and corn have more aconitate isomerase than the other species tested.
authors.affiliation: U.S. Plant, Soil, and Nutrition Laboratory, U.S. Department of Agriculture, Ithaca, New York 14853.
authors.forename: J F
authors.initials: JF
authors.lastname: Thompson
authors.forename: S C
authors.initials: SC
authors.lastname: Schaefer
authors.forename: J T
authors.initials: JT
authors.lastname: Madison
mesh_terms: D000154:Aconitate Hydratase / Q000494:pharmacology; D019748:Carbon-Carbon Double Bond Isomerases; D004226:Dithioerythritol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007535:Isomerases / Q000378:metabolism*; D010944:Plants / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors; D014908:Triticum / Q000201:enzymology; D014316:Tritium
chemical_list: D014316:Tritium; D004226:Dithioerythritol; D000154:Aconitate Hydratase; D007535:Isomerases; D019748:Carbon-Carbon Double Bond Isomerases; C018743:aconitate delta-isomerase