title: Isolation of a napin-like polypeptide with potent translation-inhibitory activity from Chinese cabbage (Brassica parachinensis cv green-stalked) seeds.
abstract: A heterodimeric napin-like polypeptide was isolated from Brassica parachinensis seeds with a procedure involving ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, FPLC-ion exchange chromatography on Mono S and FPLC-gel filtration on Superdex 75. The N-terminal sequence of the 5 kDa subunit of the polypeptide (PAGPFRIPKKRKKEE) showed high homology with other 2S storage proteins like napins and albumins. The polypeptide potently inhibited translation in a cell free system with an IC50 of 6.2 nM. The translation-inhibiting activity of the polypeptide was relatively stable in the pH range 6-11 and in the temperature range 10-50 degrees C.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Patrick H K
authors.initials: PH
authors.lastname: Ngai
authors.forename: T B
authors.initials: TB
authors.lastname: Ng
mesh_terms: D055516:2S Albumins, Plant; D000595:Amino Acid Sequence; D000818:Animals; D001937:Brassica / Q000737:chemistry*; D002474:Cell-Free System; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000302:isolation & purification* / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012639:Seeds / Q000737:chemistry*; D020539:Sequence Analysis, Protein
chemical_list: D055516:2S Albumins, Plant; D010940:Plant Proteins; C050363:napin protein, Brassica napus