title: Purification and characterization of four keratinases produced by Streptomyces sp. strain 16 in native human foot skin medium.
abstract: Four extracellular keratinases (designated KI, KII, KIII, and KIV) were produced during submerged aerobic cultivation in a medium containing native human foot skin (NHFS) for enzyme synthesis. The molecular weights, determined by SDS-PAGE, were 25, 50, 34, and 19 kDa, respectively. Gel filtration of the four purified enzymes in native conditions indicated that active keratinase KI is a novel homo-octamer, KII a homo-dimer, and KIII and KIV monomers. All four keratinases exhibited high activities at pH 8.0-10.0 with an optimal pH of 9.0. The optimal temperature for keratinolytic activity of KI, KII, and KIII was approximately 50, and 60 degrees C for KIV. One millimolar of PMSF completely inhibited the keratinolytic activities of the four enzymes. The N-terminal sequences of KI, KII, and KIII showed that they were different from previously described enzymes, whereas KIV shared an identical N-terminal sequence with two other peptidases from Streptomyces.
authors.affiliation: State Key Laboratories of Transducer Technology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Fuhong
authors.initials: F
authors.lastname: Xie
authors.forename: Yapeng
authors.initials: Y
authors.lastname: Chao
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Xue
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Luo
authors.forename: Shijun
authors.initials: S
authors.lastname: Qian
mesh_terms: D004789:Enzyme Activation; D004795:Enzyme Stability; D005528:Foot / Q000382:microbiology*; D006801:Humans; D066298:In Vitro Techniques; D010447:Peptide Hydrolases / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D012867:Skin / Q000382:microbiology*; D013045:Species Specificity; D013302:Streptomyces / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D010447:Peptide Hydrolases; C035855:keratinase