• Korean Journal of Microbiology
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• v.30 no.5
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• pp.403-409
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• 1992

For the development of a glucanolytic yeast strain. the seceretion of endo-1.4-$\beta$-D-glucanase (CMCase) of Bacillus subtilis was performed in yeast using glucoamylase gene (STA1) of Saccharomyces diastaticus. A 1.7 kb-DNA fragment of STA1 gene containing authentic promoter, signal sequence, threonine serine-rich (TS) region and N-terminal region (98 amino acids) of mature glucoamylase was ligated to YEp 24. E. coli-yeast shuttle vector. And then. CMCase structural gene of B. subtilis was fused in frame with the 1.7 kb-DNA fragment of STA1 gene, resulting in recombinant plasmid pYES('24. Yeast transformant harboring pYESC24 had no CMCase activity. So. we deleted TS region and N-terminal region of mature glucoamylase existing between signal sequence and CMCase structural gene in pYESC24. consequently constructed recombinant plasmid pYESC11. The yeast transformed with the newly constructed recombinant plasmid pYESC11 efficiently secreted CMCase to extracellular medium. After 4 days culture. total CMCase activity of this transformant was 44.7 units/ml and over 93% of total CMCase activity was detected in culture supernatant.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1573-1576
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• 2010

Bacillus subtilis PerR is a metal-dependent peroxide-sensing transcription factor which uses metal-catalyzed histidine oxidation for peroxide-sensing. PerR contains two metal binding sites, one for structural $Zn^{2+}$ and the other for the regulatory/peroxide-sensing metal. Here we investigated the effect of mutations at both the structural and regulatory metal binding sites on the oxidation of either H37 or H91, two of the peroxide-sensing ligands. All four serine substitution mutants at the structural $Zn^{2+}$ site (C96S, C99S, C136S and C139S) exhibited no detectable oxidation at histidine residues. Two of the alanine substitution mutants at regulatory metal site (H37A and D85A) exhibited selective oxidation preferentially at the H91-containing tryptic peptide, whereas no oxidation was detected in the other mutants (H91A, H93A and D104A). Our results suggest that the cysteine residues coordinating structural $Zn^{2+}$ are essential for peroxide sensing by PerR, and that the C-terminal regulatory metal binding site composed of H91, H93 and D104 can bind $Fe^{2+}$, providing a possible explanation for the peroxide sensing mechanisms by PerR.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.799-803
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• 2005

In the course of screening anti-dementia agents from natural products, two $\beta$-secretase (BACE1) inhibitors were isolated from the ethyl acetate soluble fraction of Sanguisorbae Radix by the activity-guided purification using silica gel, Sephadex LH-20, and RP-HPLC. They were identified as 1,2,3-trigalloyl-4,6-hexahydroxydiphenoyl-$\beta$-D-glucopyranoside (Tellimagrandin II, 1) and 1,2,3,4,6-pentagalloyl-$\beta$-D-glucopyranoside (2) and were shown to non-competitively inhibit $\beta$-secretase (BACE1) with the $IC_{50}$ values of $3.10{\times}10^{-6}M\;and\;3.76{\times}10^{-6}M$, respectively. The Ki values of 1 and 2 were $6.84{\times}10^{-6}M\;and\;5.13{\times}10^{-6}M$. They were less inhibitory to asecretase (TACE) and other serine proteases such as chymotrypsin, trypsin, and elastase, suggesting that they were relatively specific inhibitors of BACE1.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.311-321
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• 2003

Bacteria produce lipases, which can catalyze both the hydrolysis and the synthesis of long chain triglycerides. These reactions usually proceed with high regioselectivity and enantioselectivity, and, therefore, lipases have become very important biocatalysts used in organic chemistry. 3D lipase structures were solved from several bacterial lipases. They have an $\alpha/\beta$ hydrolase fold and a catalytic triad consisting of a nucleophilic serine, and an aspartate or glutamate residue that is hydrogen bonded to a histindine. Active sites are covered with $\alpha$-helical lid structure, of which movement is involved in the enzyme's activation at oil/water interface. Four substrate binding pockets were identified for triglycerides: an oxyanion hole and three pockets accommodating the fatty acids bound at positions sn-1, sn-2, and sn-3. These pockets determine the enantiopreference of a lipase. The understanding of structure-function relationships as well as the development of molecular evolution techniques will enable researchers to tailor new lipases for biotechnological applications.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.443-448
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• 2010

Casein phosphopeptide (CPP) enhances calcium absorption in humans. Lactic acid bacteria (LAB) are capable of synthesis of cell-surface proteinase, which can hydrolyze milk protein and release several types of peptides in the medium. This study was conducted to characterize proteinase of LAB and to evaluate the CPP production from bovine milk. The content of CPP of milk produced by cell-free extract of LAB was determined based on the quantity of decomposed peptide from casein using the O-phthaldialdehyde (OPA) method. The proteolytic activity of LAB was assayed using fluorescein isothiocyanate (FITC)-labeled casein. Casein appeared to be a better substrate than whey proteins for extracellular proteinases of LAB. During fermentation, milk proteins were hydrolyzed by extracellular proteinase of LAB, resulting in an increase in the amount of free $NH_3$ groups. Overall, the results presented here indicate that CPP produced by LAB may be a promising material for novel applications in the dairy industry.

• Journal of dental hygiene science
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• v.21 no.4
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• pp.227-232
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• 2021

Background: Cancer-associated fibroblasts (CAFs) are abundant in tumor microenvironments and interact with cancer cells to promote tumor proliferation in oral squamous cell carcinoma (OSCC). Cathepsin D (CTSD) is a soluble lysosomal aspartic endopeptidase involved in tumor proliferation and angiogenesis. In this preliminary study, we observed CTSD expression in OSCC and CAFs, postulating that CTSD might act as a bridge between OSCC and CAFs. Methods: Human epidermal keratinocytes (HEKs), OSCC, and immortalized human normal oral fibroblasts (hTERT-hNOFs) were used in this study. Additionally, we used hTERT-hNOFs transfected with an empty vector, WT (wild-type)-YAP (Yes-associated protein), and YAPS127A (YAP serine 127 to alanine). YAP127A hTERT-hNOFs activated fibroblasts similar to CAFs. To identify CTSD expression between OSCC and CAFs, conditioned medium (CM) was collected from each cell. Protein expression of CTSD was identified by western blotting. Results: To identify the expression of CTSD in fibroblasts stimulated by OSCC, we treated fibroblasts with CM from HEK and OSCC. Results indicated that hTERT-hNOFs with OSCC CM showed a weakly increased expression of CTSD compared to stimulation by HEK CM. This indicates that CAFs, YAPS127 hTRET-hNOFs, overexpress CTSD protein. HEK cells showed no CTSD expression, regardless of treatment with fibroblast CM, whereas OSCC highly expressed CTSD proteins compared with the CTSD expression in HEK cells. We also found that CTSD expression was unaffected by changes in transforming growth factor-β levels. Conclusion: This study proposes that CTSD might have potential as an interacting executor between OSCC and CAFs. Further studies are needed to investigate the role of CTSD in tumor and stromal cells.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.6.1-6.12
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• 2018

Morphine tolerance remains a challenge in the management of chronic pain in the clinic. As shown in our previous study, the dopamine D2 receptor (D2DR) expressed in spinal cord neurons might be involved in morphine tolerance, but the underlying mechanisms remain to be elucidated. In the present study, selective spinal D2DR blockade attenuated morphine tolerance in mice by inhibiting phosphatidylinositol 3 kinase (PI3K)/serine-threonine kinase (Akt)-mitogen activated protein kinase (MAPK) signaling in a ${\mu}$ opioid receptor (MOR)-dependent manner. Levo-corydalmine (l-CDL), which exhibited micromolar affinity for D2DR in D2/CHO-K1 cell lines in this report and effectively alleviated bone cancer pain in our previous study, attenuated morphine tolerance in rats with chronic bone cancer pain at nonanalgesic doses. Furthermore, the intrathecal administration of l-CDL obviously attenuated morphine tolerance, and the effect was reversed by a D2DR agonist in mice. Spinal D2DR inhibition and l-CDL also inhibited tolerance induced by the MOR agonist DAMGO. l-CDL and a D2DR small interfering RNA (siRNA) decreased the increase in levels of phosphorylated Akt and MAPK in the spinal cord; these changes were abolished by a PI3K inhibitor. In addition, the activated Akt and MAPK proteins in mice exhibiting morphine tolerance were inhibited by a MOR antagonist. Intrathecal administration of a PI3K inhibitor also attenuated DAMGO-induced tolerance. Based on these results, l-CDL antagonized spinal D2DR to attenuate morphine tolerance by inhibiting PI3K/Akt-dependent MAPK phosphorylation through MOR. These findings provide insights into a more versatile treatment for morphine tolerance.

• Journal of Integrative Natural Science
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• v.10 no.2
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• pp.95-104
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• 2017

Proviral Integration site of Moloney (Pim) murine Leukemia virus kinases is a serine/threonine specific protein kinase. It is largely involved in cell survival and proliferation. Pim-1 phosphorylates multiple cellular substrates to inhibit apoptosis and promote cell cycle progression. Over expression of Pim-1 kinase is observed in a range of malignancies and various solid cancers. High level of Pim-1 expression is seen in myeloma, acute myeloid leukemia, prostate cancer and liver carcinomas. Hence, Pim-1 is considered as an interesting cancer target. In the present study, we have performed region-focused CoMFA study on a series of imidazopyridazine derivatives as Pim-1 kinase inhibitors. A statistically acceptable region-focused CoMFA model ($q^2=0.571$; ONC=3; $r^2=0.909$) was developed. The model was then validated using Bootsrapping and progressive sampling. The contour map highlighted the regions favorable to increase the activity. Bulky substitutions in $R^2$ position of the phenyl ring could increase the activity. Similarly, small negative substitution in the $R^1$ position of the Pyridine ring could increase the activity considerably. Our results will be useful to design novel Pim-1 kinase inhibitors of this series.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.333-342
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• 2001

To detect the genetic variations among infectious bursal disease (IBD) vaccine strains, the hypervariable region of VP2 gene of seven IBDV vaccine strains were amplified using reverse transcriptase/polymerase chain reation(RT/PCR). Ampllified PCR products of IBDV were cloned, sequenced, and compared with published sequences for IBDV. Vaccine strains (JOONG, HAN, B7, IB, BU2, G2, CIL) used in Korea and Korean field isolates (SH/92, K1, 310) had 81%(310 and HAN) ~ 98%(SH/92 and CIL) amino acid sequence similarity. Vaccine strains had 80%(HAN and IB) ~ 99%(JOONG and BU2) amino acid sequence similartiy. Intermediate plus vaccine strain, CIL was not substituted at positions 279(D $\rightarrow$ N) and 284(A $\rightarrow$ T), and conserved in serine-rich heptapeptide. At the two hydrophilic region, JOONG, IB and Bu2 strains had identical amino acid sequence comparing with STC strain. By phylogenetic analysis, JOONG and DAE strains were categorized in same group with BU2. The CIL and STC strains closely related but seperated from G2, HAN, B7 and IB strains.

• BMB Reports
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• v.28 no.2
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• pp.138-142
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• 1995

An anticoagulant/fibrinolytic protease was purified to homogeneity from the earthworm Lumbricus rubellus. The protein was a single chain glycoprotein of 32 kDa that exhibited strong proteolytic activity on human thrombin and fibrin clots. Proteolytic degradation of these plasma proteins by the purified enzyme occurred at a neutral pH range. Among several human plasma proteins tested as possible substrates for the protease reaction, the 32 kDa enzyme specifically hydrolyzed both thrombin and fibrin polymers without affecting other proteins, such as serum albumin, immunoglobulin, and hemoglobin. Treatment of the purified enzyme at neutral pH with either phenylmethylsulfonylfluoride or soybean trypsin inhibitor resulted in a loss of catalytic activity. The enzyme hydrolyzed the chromogenic substrate H-D-Phe-L-Pipecolyl-L-Arg-p-nitroanilide with a $K_m$ value of 1.1 ${\mu}M$ at a neutral pH. These results suggest that the anticoagulant/fibrinolytic enzyme from Lumbricus rubellus is a member of the serine protease family having a trypsin-like active site, and one of the potential clevage sites for the enzyme is the carbonyl side of arginine residues in polypeptide chains.