title: Purification and partial chemical characterization of the antimicrobial peptide cerein 8A.
abstract: OBJECTIVE
  To purify and to characterize the antimicrobial compound cerein 8A.
  
  
  RESULTS
  Cerein 8A was isolated by ammonium sulfate precipitation, 1-butanol extraction and ion-exchange chromatography. Direct activity on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was observed. The purified substance corresponded to a 26 kDa peptide band. The native protein eluted at the void volume of Sephadex G-100, but within the included volume when a 1.5 mol l(-1) NaCl buffer was used, indicating that cerein 8A aggregates extracellularly. The antimicrobial activity was lost by treatment with proteases and heat. The ultraviolet spectrum was typical of a polypeptide and the infrared spectrum indicates that the peptide contains acyl group(s) in its structure. Intact Bacillus cereus spores were sensitive to cerein 8A at 1600 AU ml(-1).
  
  
  CONCLUSIONS
  Cerein 8A show distinct properties from other antimicrobial peptides of B. cereus, and has a significant inhibitory effect on spores.
  
  
  CONCLUSIONS
  The characterization of a substance active against important pathogens addresses an important aspect of food safety.
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Bizani
authors.forename: A P M
authors.initials: AP
authors.lastname: Dominguez
authors.forename: A
authors.initials: A
authors.lastname: Brandelli
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D001409:Bacillus cereus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D013170:Spores / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins