title: Purification and biochemical characterization of two detergent-stable serine alkaline proteases from Streptomyces sp. strain AH4.
abstract: Streptomyces sp. strain AH4 exhibited a high ability to produce two extracellular proteases when cultured on a yeast malt-extract (ISP2)-casein-based medium. Pure proteins were obtained after heat treatment (30 min at 70 °C) and ammonium sulphate fractionation (30-60 %), followed by size exclusion HPLC column. Matrix assisted laser desorption ionization-time of flight mass spectrometry analysis revealed that the purified enzymes (named SAPS-P1 and SAPS-P2) were monomers with molecular masses of 36,417.13 and 21,099.10 Da, respectively. Their identified N-terminal amino acid displayed high homologies with those of Streptomyces proteases. While SAPS-P1 was optimally active at pH 12.0 and 70 °C, SAPS-P2 showed optimum activity at pH 10.0 and 60 °C. Both enzymes were completely stable within a wide range of temperature (45-75 °C) and pH (8.0-11.5). They were noted to be completely inhibited by phenylmethanesulfonyl fluoride and diisopropyl fluorophosphates, which confirmed their belonging to the serine proteases family. Compared to SAPS-P2, SAPS-P1 showed high thermostability and excellent stability towards bleaching, denaturing, and oxidizing agents. Both enzymes displayed marked stability and compatibility with a wide range of commercial laundry detergents and significant catalytic efficiencies compared to Subtilisin Carlsberg and Protease SG-XIV. Overall, the results indicated that SAPS-P1 and SAPS-P2 can be considered as potential promising candidates for future application as bioadditives in detergent formulations.
authors.affiliation: Laboratory of Microbial Systems Biology (LMSB), École Normale Supérieure (ENS) de Kouba, PO Box 92, 16050, Kouba, Algiers, Algeria.
authors.forename: Souraya Boulkour
authors.initials: SB
authors.lastname: Touioui
authors.forename: Nadia Zaraî
authors.initials: NZ
authors.lastname: Jaouadi
authors.forename: Hadjira
authors.initials: H
authors.lastname: Boudjella
authors.forename: Fatma Zohra
authors.initials: FZ
authors.lastname: Ferradji
authors.forename: Mouna
authors.initials: M
authors.lastname: Belhoul
authors.forename: Hatem
authors.initials: H
authors.lastname: Rekik
authors.forename: Abdelmalek
authors.initials: A
authors.lastname: Badis
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.forename: Bassem
authors.initials: B
authors.lastname: Jaouadi
mesh_terms: D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D057057:Serine Proteases / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013302:Streptomyces / Q000201:enzymology / Q000254:growth & development*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D010664:Phenylmethylsulfonyl Fluoride; D057057:Serine Proteases