title: Isolation and characterization of phytochelatin synthase in rice seedlings.
abstract: Rice plants were treated with 50 microM copper sulfate to induce the synthesis of phytochelatins by means of a series of enzymatic reactions, including that of photochelatin synthase. Phytochelatin synthase extracted from 3-week-old rice seedlings was purified through a series of steps including precipitation with ice-chilled acetone, QAE A-50 anion exchange column, Amicon XM-50 ultrafiltration and Polybuffer Exchange (PBE) 94 chromato-focusing. This enzyme had a molecular mass of about 100 kDa with an isoelectric point of 4.0. The temperature and pH optima of this enzyme were 55 degrees C and pH 7.5, respectively. The enzyme was thermal tolerable and unstable under refrigeration at 4 or -20 degrees C. Cadmium was the most effective stimulator, followed by lead, copper, silver, cobalt and other divalent cations. Calcium and magnesium had no effect.
authors.affiliation: Department of Botany, National Taiwan University, Taipei, ROC.
authors.forename: S L
authors.initials: SL
authors.lastname: Yan
authors.forename: C C
authors.initials: CC
authors.lastname: Tsay
authors.forename: Y R
authors.initials: YR
authors.lastname: Chen
mesh_terms: D000096:Acetone; D019881:Aminoacyltransferases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000838:Anions; D002104:Cadmium / Q000494:pharmacology; D002413:Cations, Divalent; D002845:Chromatography; D002852:Chromatography, Ion Exchange; D019327:Copper Sulfate / Q000494:pharmacology; D004795:Enzyme Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D012275:Oryza / Q000187:drug effects / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000032:analysis; D014462:Ultrafiltration
chemical_list: D000838:Anions; D002413:Cations, Divalent; D013438:Sulfhydryl Compounds; D002104:Cadmium; D000096:Acetone; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase; D019327:Copper Sulfate