A novel detergent-stable solvent-tolerant serine thiol alkaline protease from Streptomyces koyangensis TN650

• Published in: International journal of biological macromolecules Vol. 79; pp. 871 - 882
• Main Authors: Ben Elhoul, Mouna, Zaraî Jaouadi, Nadia, Rekik, Hatem, Bejar, Wacim, Boulkour Touioui, Souraya, Hmidi, Maher, Badis, Abdelmalek, Bejar, Samir, Jaouadi, Bassem
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-08-2015
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Detergent; Detergents - chemistry; Endopeptidases - chemistry; Endopeptidases - isolation & purification; Endopeptidases - metabolism; Enzyme Stability; Hydrolysis; Kinetics; Protease; RNA, Ribosomal, 16S - genetics; Serine Proteases - chemistry; Serine Proteases - isolation & purification; Serine Proteases - metabolism; Solvents - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptomyces; Streptomyces - enzymology; Substrate Specificity; Temperature; Streptomyces; Protease; Detergent
• DOI: 10.1016/j.ijbiomac.2015.06.006
• EISSN: 1879-0003
• ISSN: 0141-8130

•The paper reports on an extracellular protease from S. koyangensis strain TN650.•The thiol serine protease (called STAP) was purified and biochemically characterized.•The optimum pH and temperature values for activity were pH 10 and 70°C, respectively.•The stap gene encoding STAP was cloned in E. coli, and its sequence was determined.•STAP is a promising biocatalyst for the synthesis peptides and detergent formulations.
An alkaline proteinase (STAP) was produced from strain TN650 isolated from a Tunisian off-shore oil field and assigned as Streptomyces koyangensis strain TN650 based on physiological and biochemical properties and 16S rRNA gene sequencing. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer with a molecular mass of 45125.17-Da. The enzyme had an NH2-terminal sequence of TQSNPPSWGLDRIDQTTAFTKACSIKY, thus sharing high homology with those of Streptomyces proteases. The results showed that this protease was completely inhibited by phenylmethanesulfonyl fluoride (PMSF), diiodopropyl fluorophosphates (DFP), and partially inhibited by 5,5-dithio-bis-(2-nitro benzoic acid) (DTNB), which strongly suggested its belonging to the serine thiol protease family. Using casein as a substrate, the optimum pH and temperature values for protease activity were pH 10 and 70°C, respectively. The protease was stable at pH 7–10 and 30–60°C for 24h. STAP exhibited high catalytic efficiency, significant detergent stability, and elevated organic solvent resistance compared to the SG-XIV proteases from S. griseus and KERAB from Streptomyces sp. AB1. The stap gene encoding STAP was isolated, and its DNA sequence was determined. These properties make STAP a potential candidate for future application in detergent formulations and non-aqueous peptide biocatalysis.