ABSTRACT
An oligopeptidase from Bacillus amyloliquefaciens 23-7A was characterized along with its biochemical activities and structural gene. The protein's amino acid sequence and enzymatic activities were similar to those of other bacterial PepFs, which belong to metallopeptidase family M3. While most bacterial PepFs are cytoplasmic endopeptidases, the identified PepFBa oligopeptidase is a secreted protein and may facilitate the process of sporulation.
Subject(s)
Bacillus/enzymology , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Metalloendopeptidases/chemistry , Metalloendopeptidases/metabolism , Amino Acid Sequence , Bacillus/genetics , Bacillus/physiology , Bacterial Proteins/genetics , Bacterial Proteins/physiology , Metalloendopeptidases/genetics , Metalloendopeptidases/physiology , Molecular Sequence Data , Sequence Analysis, DNA , Substrate SpecificityABSTRACT
Scopoletin was isolated from Sinomonium acutum and studied using four experimental models designed to assess antioxidant properties. The results indicated that scopoletin scavenged superoxide anion in the xanthine/xanthine oxidase reaction system in a concentration-dependent manner, but did not inhibit xanthine oxidase. Scopoletin may therefore be responsible for the superoxide anion scavenging activity seen in Sinomonium acutum extracts and may be of use in preventing superoxide anion-induced damage in vivo.
Subject(s)
Antioxidants/pharmacology , Free Radical Scavengers/pharmacology , Phytotherapy , Scopoletin/pharmacology , Sinomenium/chemistry , Antioxidants/administration & dosage , Antioxidants/therapeutic use , Biphenyl Compounds , Dose-Response Relationship, Drug , Drugs, Chinese Herbal/administration & dosage , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Free Radical Scavengers/administration & dosage , Free Radical Scavengers/therapeutic use , Humans , Hydrogen Peroxide , Hydroxyl Radical , Picrates , Plant Stems/chemistry , Scopoletin/administration & dosage , Scopoletin/therapeutic use , SuperoxidesABSTRACT
Bioassy-directed fractionation of a culture broth of Penicillium citrinum F5 led to the isolation of a novel antioxidant 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (1), together with gentisic acid (2), and their structures were determined on the basis of spectroscopic data. In the 1,1-diphenyl-picryl-hydrazyl (DPPH) assay system, compounds 1 and 2 showed free radical scavenging activity with IC(20) values of 10.39 and 4.26 microM, respectively.
Subject(s)
Antioxidants/isolation & purification , Benzofurans/isolation & purification , Free Radical Scavengers/isolation & purification , Penicillium/chemistry , Antioxidants/chemistry , Antioxidants/pharmacology , Benzofurans/chemistry , Benzofurans/pharmacology , Biphenyl Compounds , Chromatography, High Pressure Liquid , Free Radical Scavengers/chemistry , Free Radical Scavengers/pharmacology , Inhibitory Concentration 50 , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Picrates , TaiwanABSTRACT
Extracellular leucine aminopeptidase (LAP) from Aspergillus sojae was purified to protein homogeneity by sequential fast protein liquid chromatography steps. LAP had an apparent molecular mass of 37 kDa, of which approximately 3% was contributed by N-glycosylated carbohydrate. The purified enzyme was most active at pH 9 and 70 degrees C for 30 min. The enzyme preferentially hydrolyzed leucine p-nitroanilide followed by Phe, Lys, and Arg derivatives. The LAP activity was strongly inhibited by metal-chelating agents, and was largely restored by divalent cations like Zn(2+) and Co(2+). The lap gene and its corresponding cDNA fragment of the A. sojae were cloned using degenerated primers derived from internal amino acid sequences of the purified enzyme. lap is interrupted by three introns and is transcribed in a 1.3-kb mRNA that encodes a 377-amino-acid protein with a calculated molecular mass of 41.061 kDa. The mature LAP is preceded by a leader peptide of 77 amino acids, predicted to include an 18-amino-acid signal peptide and an extra sequence of 59 amino acids. Two putative N-glycosylation sites are identified in Asn-87 and Asn-288. Southern blot analysis suggested that lap is a single-copy gene in the A. sojae genome. The deduced amino acid sequence of A. sojae LAP shares only 11-33.1% identity with those of LAPs from 18 organisms.
