title: Purification, characterization, and properties of an alkaline protease produced by Serratia marcescens S3-R1 inhabiting Korean ginseng rhizosphere.
abstract: BACKGROUND
  An alkaline protease produced by the Serratia marcescens S3-R1 which inhabits in the Korean ginseng rhizosphere was investigated. The purposes of this study were to characterize and purify the bacterial enzyme by four different purification steps: precipitation of enzyme fraction by ammonium sulfate, loading the enzyme pellets on a DEAE-Sepharose anion-exchange chromatograph, separation of the fraction containing enzyme activity by fast protein liquid Mono Q chromatography and identification of the single-band fraction by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and then quantification of the single-band fraction by reverse-phase high-performance liquid chromatography.
  
  
  RESULTS
  The molecular weight of the purified protease was estimated as 50 308 Da by matrix-assisted laser desorption ionization time-of-flight analysis. The N-terminal amino acid sequence of the protease was identified as Ala-Val-Thr-Ile-Glu-Asp-Ala-Val-Asp-Asp, and the enzyme belongs to the metalloprotease family. The optimal activities of the protease occurred at pH 7-9 and a temperature 40 °C. The ranges of pH and thermal stability of the enzyme were at 7-10 and 30-40 °C, respectively.
  
  
  CONCLUSIONS
  The alkaline protease was successfully purified and characterized from the bacterium Serratia marcescens S3-R1, which has potential for industrial application, including milk protein hydrolysates.
authors: Department of Animal Bio-system Science, College of Agriculture and Life Sciences, Chungnam National University, Yuseong-gu, Daejeon, 305-764, Republic of Korea.
authors: Myoung Soo
authors: MS
authors: Nam
authors: Kyung Sook
authors: KS
authors: Whang
authors: Seong Hyun
authors: SH
authors: Choi
authors: Hyoung Churl
authors: HC
authors: Bae
authors: Yoo Kyeong
authors: YK
authors: Kim
authors: Young W
authors: YW
authors: Park
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification*; D010450:Endopeptidases / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D005894:Panax / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology*; D058441:Rhizosphere; D012706:Serratia marcescens / Q000201:enzymology*; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D010450:Endopeptidases; C087822:alkaline protease
keywords: Serratia marcescens S3-R1; molecular weight; protease; purification