title: Alkaline serine protease produced by Streptomyces sp. degrades PrP(Sc).
abstract: A PrP(Sc)-degrading enzyme was isolated from the culture medium of Streptomyces sp. using perchloric acid-soluble protein (PSP) as a substrate. The media of 500 microbial species were screened to obtain the PSP-degrading enzyme. The medium containing the protease secreted from strain 99-GP-2D-5 showed the highest PSP-degrading activity. Strain 99-GP-2D-5 was assigned as the genus Streptomyces by its morphological and chemotaxonomic characteristics. When scrapie prion was used as the substrate, it was completely digested by the enzyme. The amino acid sequence of the enzyme was identical to that of the C-terminal region of alkaline serine protease (ASP) I. ASP I may be the precursor of the enzyme, and the enzyme seems to be the mature type of ASP I. The maximal activity of the enzyme was observed at 60 degrees C and pH 11, and the scrapie prion was degraded within 3 min under the optimum conditions.
authors.affiliation: Department of Veterinary Physiology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Hui
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Doi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanouchi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Matsuura
authors.forename: Shiro
authors.initials: S
authors.lastname: Mohri
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nonomura
authors.forename: Tatsuzo
authors.initials: T
authors.lastname: Oka
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D006224:Cricetinae; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D018620:PrPSc Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013302:Streptomyces / Q000201:enzymology*; D014357:Trypsin
chemical_list: D001426:Bacterial Proteins; D010446:Peptide Fragments; D018620:PrPSc Proteins; D012697:Serine Endopeptidases; C493013:alkaline serine protease I, Streptomyces; D014357:Trypsin