title: [Purification of a big defensin from Ruditapes philippinesis and its antibacterial activity].
abstract: A novel big defensin was isolated and characterized from the plasma of Ruditapes philippinesis. It was purified to homogeneity by means of precipitation with (NH(4))(2)SO(4), gel-exclusion chromatography, two kinds of cation-exchange chromatography and named RPD-1. Its relative molecular mass was 24.8 kD by means of SDS-PAGE. By means of ABI437 amino acid sequence analyser, its 11 NH(2)-terminal amino acid sequence is AVPDVAFNAYG. Two databank systems (NCBI and EBI/EMBL) was indexed, no sequence with homology to RPD-1 was found. Furthermore, it exhibited strong inhibition on the growth of Gram-negative and -positive bacteria. Minimal inhibitory concentration (MIC) of RPD-1 against Staphylococcus aureus, Bacillus subtilis, Micrococcus tetragenus, Escherichia coli, Vibrio parahaemolyticus, Vibrio anguillarum was 9.6 mg/L, 76.8 mg/L, 38.4 mg/L, 76.8 mg/L, 19.2 mg/L, 19.2 mg/L respectively.
authors.affiliation: Department of Biology, Qingdao University, Qingdao 266071, China. weiyuxi@sohu.com
authors.forename: Yu-Xi
authors.initials: YX
authors.lastname: Wei
authors.forename: Dao-Sen
authors.initials: DS
authors.lastname: Guo
authors.forename: Rong-Gui
authors.initials: RG
authors.lastname: Li
authors.forename: Hao-Wen
authors.initials: HW
authors.lastname: Chen
authors.forename: Pei-Xun
authors.initials: PX
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D049872:Bivalvia / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002845:Chromatography / Q000379:methods; D023082:Defensins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D020539:Sequence Analysis, Protein
chemical_list: D000900:Anti-Bacterial Agents; D001798:Blood Proteins; D023082:Defensins