• Journal of Microbiology and Biotechnology
• /
• 제15권3호
• /
• pp.573-578
• /
• 2005

Pyrimidine nucleotide N-ribosidase (pyrimidine 5'-nucleotide phosphoribo(deoxyribo)hydrolase/pyrimidine 5'-nucleotide nucleosidase, EC 3.2.2.10) catalyzes the breakdown of pyrimidine 5'-nucleotide into pyrimidine base and ribose(deoxyribo)-5-phosphate. However, detailed characteristics of the enzyme have not yet been reported. The enzyme was purified to homogeneity 327.9-fold with an overall yield of $6.1\%$ from Pseudomonas oleovorans ATCC 8062. The enzyme catalyzed cytidine monophosphate (CMP) and uridine monophosphate (UMP), but not adenosine monophosphate (AMP) and guanosine monophosphate (GMP). The enzyme optimally metabolized CMP at pH 6.0 and UMP at around 8.5, and the optimum temperature for the overall enzyme reaction was found to be $37^{\circ}C$. The $K_m$ values of the enzyme for CMP (at pH 6.0) and UMP (at pH 8.5) were 1.6 mM and 1.1 mM, respectively. AMP, deoxyCMP, and deoxyUMP were very effective inhibitors of the reaction. Double-reciprocal plots obtained in the absence and in the presence of AMP revealed that this inhibitory effect was of the mixed competitive type with respect to the breakdown of CMP and of the noncompetitive type with respect to the breakdown of UMP. In the presence of AMP, the enzyme followed sigmoid kinetics with respect to each substrate.

• Fisheries and Aquatic Sciences
• /
• 제3권3_4호
• /
• pp.188-194
• /
• 2000

A protease purified from hepatopancreas of shrimp, Penaeus japonicus, had maximum activity at $70^{\circ}C$ and in neutral and alkaline pH ranges. Specific activity at optimum reaction condition of the protease was estimated to be approximately 12 U/mg/min. The protease was stable in neutral and alkaline pH ranges and activity was retained after heat treatment at $50^{\circ}C$ for 30 min. Apparent $K_m$ and $V_{max}$ value against casein substrate were estimated to be $0.29\%$ and $7.8see^{-1}$, respectively, and those against N-CBZ-L-tyrosine p-nitropheny1 ester (CBZ­Tyr-NE) were 0.38 mM and $2,400 see^{-1}$, respectively. The N-termina1 sequence of the protease showed high homology to the trypsin from same species and the proteases from shrimp. Myosin heavy chain (MHC) from shrimp tail meat was the most susceptible to the protease and actin/tropomyosin were degraded progressively during 4 hr incubation, but to a lesser degree than MHC.

• BMB Reports
• /
• 제33권4호
• /
• pp.326-331
• /
• 2000

Acidic chitinases from the gizzards of a broiler were purified to homogeneity, using precipitation with $(NH_{4})_{2}SO_{4}$, ion exchanger chromatography, gel filtration, chromatofocusing and hydrophobic interaction chromatography. The enzymes, GAC1 and GAC2, were purified 180- and 194- folds with a recovery of 4.9% and 2.7%, respectively. The molecular mass of GAC1 and GAC2 were 48.2 kDa and 57.8 kDa, respectively. Chromatofocusing resulted in a pI of 3.1 for both enzymes. The purified enzymes were endochitinases that were devoid of ${\beta}-N-acetylglucosaminidase$ and lysozyme activity. Kinetic studies using $[^3H]chitin$ indicate that GAC1 has a $K_m$ and $V_{max}$ of 1.97 mg/ml and 185 mg/mg protein/h, respectively. The GAC2 has a $K_m$ and $V_{max}$ of 0.42 mg/ml and 92.3 mg/mg protein/h, respectively at optimal pH and temperature (pH 5.0 and $60^{\circ}C$). When the pentamer and hexamer of N-acetylglucosamine (GlcNAc) were used as a substrate, the major product by GAC1 was the dimer of GlcNAc with a differential accumulation of the monomer and trimer, depending upon the substrate. However, the GAC2 produced the dimer and trimer in an equal quantity, regardless of the substrate used. The first 9 $NH_2-terminal$ amino acid residues of the purified gizzard chitinase GAC1 and GAC2 shared a 100% homology. The first 25 $NH_2-terminal$ amino acid residues of GAC1 also shared 55-60% homology with animal chitinases and some animal proteins, such as whey protein and oviduct-specific proteins. However, little homology was found with either microbial and plant chitinases, or egg white lysozyme.

• Mycobiology
• /
• 제35권4호
• /
• pp.219-225
• /
• 2007

A keratinolytic enzyme secreted by Aspergillus flavus K-03 cultured in feather meal basal medium (FMBM) containing 2% (w/v) chicken feather was purified and characterized. Keratinolytic enzyme secretion was the maximal at day 16 of the incubation period at pH 8 and $28^{\circ}C$. No relationship was detected between enzyme yield and increase of fungal biomass. The fraction obtained at 80% ammonium sulfate saturation showed 2.39-fold purification and was further purified by gel filtration in Sephadex G-100 followed by ion exchange chromatography on DEAE-Sephadex A-50, yielding an active protein peak showing 11.53-fold purification. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and zymograms indicated that the purified keratinase is a monomeric enzyme with 31 kDa molecular weight. The extracellular keratinase of A. flavus was active in a board range of pH ($7{\sim}10$) and temperature ($30^{\circ}C{\sim}70^{\circ}C$) profiles with the optimal for keratinase activity at pH 8 and $45^{\circ}C$. The keratinase activity was totally inhibited by protease inhibitors such as phenylmethylsulfonyl fluoride (PMSF), iodoacetic acid, and ethylenediaminetetraacetate (EDTA) while no reduction of activity by the addition of dithiothreitol (DTT) was observed. N-terminal amino acid sequences were up to 80% homologous with the fungal subtilisins produced by Fusarium culmorum. Therefore, on the basis of these characteristics, the keratinase of A. flavus K-03 is determined to be subtilisins-like.

• Journal of Applied Biological Chemistry
• /
• 제42권4호
• /
• pp.166-168
• /
• 1999

Inulo-oligosaccharides (IOS, $F_n$, n=2-6) were purified from enzymatic hydrolysates of water-soluble extract of Jerusalem artichoke tubers. Quantification of inulo-oligosaccharides was done using high pH anion exchange chromatography with pulsed amperometric detector (HPAEC-PAD) at the concentration range of 10-100 mg/L, which was compared with that of fructo-oligosaccharides (FOS, $GF_n$, n=1-7). Peak areas per mg IOS were higher than FOS at the same degree of polymerization (DP). Specific peak areas of IOS increased proportionally as DP increased up to six, in contrast to FOS showing no linearity.

• Journal of Microbiology
• /
• 제40권1호
• /
• pp.20-25
• /
• 2002

An extracellular PHB depolymerase was purified from P. simplicissimum LAR13 cultural medium by Sepharose CL-6B chromatography. When the fungus was grown in a basal salt medium with poly(3-hydroxybutyrate) (PHB) as the sole carbon source, PHB depolymerase production reached maximum at its stationary phase. The mycelial growth rate was higher at 37$^{\circ}C$ than at 30$^{\circ}C$ and even higher than at 25$^{\circ}C$, However, the enzyme production was lower at 37$^{\circ}C$ than 30$^{\circ}C$ or 25$^{\circ}C$. The isolated enzyme is composed of a single polypeptide chain with a molecular mass of about 36 kDa as determined by SDS-PAGE. The optimum conditions for the enzyme activity are pH 5.0 and 45$^{\circ}C$. The enzyme was stable for 30 min at a temperature lower than 50$^{\circ}C$, and stable at pH higher than 2.0 but it was unstable at pH 1.0.1 mM Fe$\^$2+/ reduced the enzyme activity by 56% and the enzyme was inhibited almost completely by 4 mM Fe$\^$2+/ . The enzyme was partially inhibited by phenylmethylsulfonyl fluoride and was very sensitive to diazo-DL-norleucine methyl esters dithiothreitol and mercuric ion. However, N-p - tosyl - L - Iysinechloromethyl ketone, p -hydroxymercuricbenzoate and N- acetylimidazole had no influence upon its activity.

• Archives of Pharmacal Research
• /
• 제28권8호
• /
• pp.923-929
• /
• 2005

Methanol extracts of domestic plants of Korea were evaluated as a potential inhibitor of neutral pH optimum and membrane-associated 60 kDa sphingomyelinase (N-SMase) activity. In this study, we partially purified N-SMase from bovine brain membranes using ammonium sulfate. It was purified approximately 163-fold by the sequential use of DE52, Butyl-Toyopearl, DEAE-Cellulose, and Phenyl-5PW column chromatographies. The purified N-SMase activity was assayed in the presence of the plant extracts of three hundreds species. Based on the in vitro assay, three plant extracts significantly inhibited the N-SMase activity in a time- and concentration-dependent manner. To further examine the inhibitory pattern, a Dixon plot was constructed for each of the plant extracts. The extracts of Abies nephrolepis, Acer tegmentosum, and Ginkgo biloba revealed a competitive inhibition with the inhibition constant (Ki) of $11.9 {\mu}g/mL,\;9.4{\mu}g/mL,\;and\;12.9{\mu}g/mL$, respectively. These extracts also inhibited in a dose-dependent manner the production of ceramide induced by serum deprivation in human neuroblastoma cell line SH-SY5Y.

• Biomedical Science Letters
• /
• 제2권1호
• /
• pp.21-30
• /
• 1996

MAP kinases are a family of serine/threonine specific protein kinases becoming activated in response to different proliferative stimuli by phosphorylation at both threonine and tyrosine residue. Present study shows that MAP kinase was purified from P388 murine leukema cells by SP sephadex C-50, phenyl superose and Mono Q column chromatography and identified with anti-ERKl antibody by western blotting. Immnublotting analysis to the crude extract of P388 cell lysate shows 44 kD and other minor bands but partial purified fraction eluted from phenyl supherose column have 44kD and 66 kD isoform. Subcloned GST-fusion protein from N-terminal of $p56^{kk}$ was tested as a substrate for MAP kinase phosphorylation. It was showed that the wild type and mutant forms(S42A) were fully phosporylated by purified MAP kinase fraction as com-pare with the other mutant form(S59A). This finding suggest that those GST-fusion proteins may be used as substrate for the in vitro test of MAP kinase.

• Journal of Microbiology and Biotechnology
• /
• 제20권7호
• /
• pp.1069-1076
• /
• 2010

A novel laccase from Tricholoma mongolicum was purified by using a procedure that entailed ion-exchange chromatographies on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and FPLC-gel filtration on Superdex 75. The purified enzyme was obtained with a specific activity of 1,480 U/mg-protein and a final yield of 15%. It was found to be a monomeric protein with a molecular mass of 66 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its N-terminal amino acid sequence was GIGPVADLYVGNRIL, similar to some but also different to other mushroom laccases. The optimum pH and temperature for the purified enzyme were pH 2 to pH 3 and $30^{\circ}C$, respectively. It displayed a low $K_m$ toward 2,7-azinobis (3-ethylbenzothiazolone-6-sulfonic acid) diammonium salt (ABTS) and high $k_{cat}/K_m$ values. The purified laccase oxidized a wide range of lignin-related phenols, but exerted maximal activity on ABTS. It was significantly inhibited by $Hg^{2+}$ ions, and remarkably stimulated by $Cu^{2+}$ ions. It inhibited HIV-1 reverse transcriptase and proliferation of hepatoma HepG2 cells and breast cancer MCF7 cells with an $IC_{50}$ of 0.65 ${\mu}M$, 1.4 ${\mu}M$, and 4.2 ${\mu}M$, respectively, indicating that it is also an antipathogenic protein.

• Korean Journal of Veterinary Research
• /
• 제46권2호
• /
• pp.127-133
• /
• 2006

Pasteurella multocida is a terrible veterinary pathogen that causes widespread infections in husbandry. To induce homologous and/or heterologous immunity against the infections, outer membrane protein Hs (OmpH) in the envelope of different strains of P. multocida are thought to be attractive vaccine candidates. Previously we cloned and characterized a gene for OmpH from pathogenic P. multocida (A : 3) (In Press, Korean J. Microbiol. Biotechnol. 2005, 33, December). The gene is composed of 1,047 nucleotides (nt) coding 348 amino acids (aa) with signal peptide of 20 aa. The truncated ompH, a gene without nt coding for the signal peptide, was generated using pRSET A to name "pRSET A/OmpH-F2". This truncated ompH was well expressed in Escherichia coli BL21 (DE3). Truncated OmpH was purified for induction of immunity against live pathogen of fowl cholera (P. multocida A : 3) in mice. Some $50{\mu}g$ of the purified polypeptide was intraperitoneally injected into mice two times with 10 day interval. Lethal dose ($25{\mu}l$) of live P. multocida A : 3 was determined by directly injecting the pathogen into wild mice (n = 25). To demonstrate the vaccine candidate of the truncated OmpH, the live pathogen ($25{\mu}l$) was challenged with the OmpH-immunized mouse group as well as positive & negative controls (n = 80). The results show that the truncated OmpH can be used for an effective vaccine production to prevent fowl cholera caused by pathogenic P. multocida (A : 3).