• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1629-1633
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• 2015

Peptide assimilation in Helicobacter pylori necessitates a coordinated working of the peptide transport systems (PepTs) and aminopeptidase (PepA). We found that H. pylori hydrolyzes two detector peptides, _L-phenylalanyl- _L-3-thiaphenylalanine (PSP) and _L-phenylalanyl- _L-2-sulfanilylglycine (PSG), primarily before intake and excludes their antibacterial effects, whereas Escherichia coli readily transports them with resultant growth inhibition. PSP assimilation by H. pylori was inhibited by aminopeptidase inhibitor bestatin, but not by dialanine or cyanide-m-chlorophenylhydrazone, contrary to that of E. coli. RT- and qRT-PCR analyses showed that H. pylori may express first the PepTs (e.g., DppA and DppB) and then PepA. In addition, western blot analysis of PepA suggested that the bacterium secretes PepA in response to specific inducers.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.04a
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• pp.77-90
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• 2006

Beta-amyloid peptide (A$\beta$) is a major component of senile plaques and its aggregation is considered to play a critical role in pathogenesis of Alzheimer's disease (AD). Aggregation of A$\beta$ could result from both increased synthesis and decreased degradation of A$\beta$. Our laboratory is interested in understanding the mechanism of A$\beta$ degradation in brain. Recently our laboratory identified a bacterial gene (SKAP) from Streptomyces sp KK565 whose protein product has an activity to cleave A$\beta$ and thus reduce the A$\beta$-induced neurotoxicity. The sequence analysis showed that this gene was closely related to aminopeptidase. Maldi-Tof analysis showed that the recombinant SKAP protein expressed in E. coli cleaves both A$\beta$ 40 and A$\beta$ 42 at the N-terminal of A$\beta$ while an aminopeptidase from Streptomyces griseus (SGAP) cleaves at the C-terminal. We also identified a mammalian homolog of SKAP and the recombinant mammalian protein expressed in Sf-9 insect cells showed a similar proteolytic activity to SGAP, cutting A$\beta$ at the C-terminus. I well discuss the detailed mechanism of the enzyme action and its functional implication in AD.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.959-963
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• 2015

Purpose: To find parameters that can increase alpha-fetoprotein (AFP) sensitivity and so help in accurate diagnosis and rapid management of hepatocullular carcinoma (HCC), as AFP has limited utility of distinguishing HCC from benign hepatic disorders for its high false-positive and false negative rates. Materials and Methods: Serum levels of AFP, 5'-nucleotidase enzyme activity (5-NU) and leucine aminopeptidase enzyme (LAP) activity were measured in 40 individuals. Results: LAP and 5'NU were elevated in HCC at p<0.001. Pearson correlation coefficients showed that changes in AFP exhibited positive correlation with both 5'-NU and LAP at (p<0.001). The complementary use of LAP only with AFP resulted in an increase in sensitivity of AFP from 75% to 90% in detecting HCC. The complementary use of both LAP and 5-NU with AFP resulted in an increased sensitivity of AFP in detecting HCC from 75% to 95%. Conclusions: LAP and 5-FU can be determined in HCC patients in combination with AFP to improve its sensitivity and decrease false negative results.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.158-162
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• 1995

The effect of carbon and nitrogen sources on the production of novel aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 has been studied. High D-glucose and ammonia concentrations (5$\%$ and 1$\%$, respectively) exerted a negative influence on the inhibitor formation. The suppressive effect of glucose on the inhibitor formation is probably caused by an effect of medium pH rather than that of cyclic AMP. To establish the optimum conditions for inhibitor overproduction, various nitrogen sources and ammonium ion-trapping agents were examined. The use of ammonia slow-releasing nitrogen sources such as soybean meal and fish meal, or ammonium ion-trapping agents such as kaoline, celite, and natural zeolite achieved the enhancement of inhibitor production. These results also indicate that inhibitor formation is affected by ammonium ion repression.

• BMB Reports
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• v.35 no.2
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• pp.228-235
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• 2002

Methionine aminopeptidase (MetAP) catalyzes the removal of an amino-terminal methionine from a newly synthesized polypeptide. The enzyme was purified to homogeneity from Bacillus stearothermophilus (KCTC 1752) by a procedure that involves heat precipitation and four sequential chromatographs (including DEAE-Sepharose ion exchange, hydroxylapatite, Ultrogel AcA 54 gel filtration, and Reactive red 120 dye affinity chromatography). The apparent molecular masses of the enzyme were 81,300 Da and 41,000 Da, as determined by gel filtration chromatography and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), respectively. This indicates that the enzyme is comprised of two identical subunits. The MetAP specifically hydrolyzed the N-terminal residue of Met-Ala-Ser that was used as a substrate, and exhibited a strong preference for Met-Ala-Ser over Leu-Gly-Gly, Leu-Ser-Phe, and Leu-Leu-Tyr. The enzyme has an optimal pH at 8.0, an optimal temperature at $80^{\circ}C$, and pI at 4.1. The enzyme was heat-stable, as its activity remained unaltered when incubated at $80^{\circ}C$ for 45 min. The Km and Vmax values of the enzyme were 3.0mM and 1.7 mmol/min/mg, respectively. The B. stearothernmophilus MetAP was completely inactivated by EDTA and required $Co^{2+}$ ion(s) for activation, suggesting the metal dependence of this enzyme.

• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.213-217
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• 1995

The effect of inorganic phosphate on the fermentative production of aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 has been studied. With inorganic phosphate concentrations higher than 0.78 mM, an inverse correlation was found between the maximum inhibitor production and the initial phosphate concentration added. Growth sensitivity of this actinomycete to arsenate, a phosphate analogue, and the use of magnesium carbonate, a phosphate-trapping agent, suggested that the inhibitor formation was under phosphate repression. Exogenous ATP further increased the degree of phosphate interference in both phosphate-repressed and non repressed culture conditions. The use of a phosphate analogue and a protein synthesis inhibitor also suggested that the phosphate itself repressed inhibitor formation.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.26-31
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• 2023

A map gene encoding methionyl-specific aminopeptidase (MAP; EC 3.4.11.18) was cloned from Tetragenococcus halophilus CY54. Translated amino acid sequence of CY54 MAP showed high similarities with those from Enterococcus faecalis (83.8%) and Streptococcus salivarius (62.2%) but low similarities with MAPs from Lactobacillus and Lactococcus genera. The map gene was overexpressed in E. coli BL21(DE3) using pET26b(+),pET26b(+), and the recombinant MAP was purified by using an Ni-NTA column. The size of recombinant MAP was 29 kDa as determined by SDS-PAGE. The optimum pH and temperature of CY54 MAP were pH 5.0 and 60℃, respectively. The activity of CY54 MAP was most significantly increased by Co²⁺ ion (159%), and showed the highest activity at 12% NaCl. K_m and V_max were 0.64 ± 0.006 mM and 10.12 ± 0.014 U/mg protein, respectively when met-pNA was used as the substrate. This is the first report on a MAP from Tetragenococcus species.

• Journal of Microbiology and Biotechnology
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• v.33 no.3
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• pp.371-377
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• 2023

In this study, a pepA gene encoding glutamyl (aspartyl)-specific aminopeptidase (PepA; E.C. 3.4.11.7) was cloned from Tetragenococcus halophilus CY54. The translated PepA from T. halophilus CY54 showed very low similarities with PepAs from Lactobacillus and Lactococcus genera. The pepA from T. halophilus CY54 was overexpressed in E. coli BL21(DE3) using pET26b(+). The recombinant PepA was purified by using an Ni- NTA column. The size of the recombinant PepA was 39.13 kDa as determined by SDS-PAGE, while its optimum pH and temperature were pH 5.0 and 60℃, respectively. In addition, the PepA was completely inactivated by 1 mM EDTA, indicating its metallopeptidase nature. The Km and Vmax of the PepA were 0.98 ± 0.006 mM and 0.1 ± 0.002 mM/min, respectively, when Glu-pNA was used as the substrate. This is the first report on PepA from Tetragenococcus species.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.91-93
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• 2001

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.530-536
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• 2009

Cobalt chloride ($CoCl_2$) treatment of cells in vitro has been shown to induce cellular changes that are similar to those seen following hypoxia. To identify genes that are differentially expressed in response to treatment with $CoCl_2$, we compared the mRNA expression profiles of PC-3 cells that were treated with $CoCl_2$ with those of untreated PC-3 cells, using specific arbitrary primers and two anchored oligo(dT) primers provided in the ACP-based GeneFishing kits. The results of this study demonstrated that the puromycin-sensitive aminopeptidase (PSA) gene was down regulated in PC-3 cells that were treated with $CoCl_2$. This downregulation of PSA expression, in turn, suppressed the proliferation, migration, and invasion of PC-3 cells, as well as the secretion and expression of matrix metalloproteinase-9 (MMP-9).