• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.733-735
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• 2003

Ornithine decarboxylase (ODC) is a key enzyme on the regulation of cellular polyamines. ODC antizyme is a protein that represses ODC through accelerating enzymatic degradation by the 26S proteasome. We have isolated two distinct antizyme cDNA clones (AZS and AZL) from a brain cDNA library constructed with flounder (Paralichthys olivaceus). AZS and AZL cDNA clones were encoding 221 and 218 residues long respectively and revealed 57.7% amino acids sequence identity. The presence of two antizymes mRNA were detected in brain, kidney, liver, and embryo.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.1
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• pp.40-45
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• 1991

The release of hepatic triglyceride lipase from cultured rat hepatocytes and its hormonal regulation were studied. The activity of lipase released into the medium in the presence of heparin was increasing during 24 hours on the 2nd of culture while this was 10% in the absence of heparin as compared with the lipase activity in the presense of heparin. When hepatocytes were cultured with anti-hepatic triglyceride lipase lgG the lipase activity was supp-ressed by 92% The results suggest that the enzyme relaeased into culture medium is identical to hepatic triglyceride lipase which can be released only in the presence of heparin the model of release being similar to that of lipoprotein lipase from adipocytes. The addition of monensin to the medium resulted in The inhibition of lipase secretion by 61% Insulin enhanced lipase activity only 20% whereas dexamethasone suppressed the activity by 44% These data inidica-ted that hepatic triglyceride lipase is secreted and released from hepatocytes in the presence of heparin and its secretion is regulated by hormones.

• Environmental Mutagens and Carcinogens
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• v.10 no.1
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• pp.1-10
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• 1990

The regulation of DNA repair genes expression was investigated using fused genes, in which the promoter of repair genes was hybridized with the lacZ structural gene. The activities of beta-galactosidase expressed from the fused gense were highly increased when the host cells were exposed to methylating agents, such as methyl methansulfonate (MMS), N-methyl-N'-nitro-nitrosoguanidine (MNNG) and methyl nitrosourea (MNU). On the other hand, the enzyme activities from the fused genes were not induced when the cells were treated with ethylating or nonalkylating agents, such as ethyl methansulfonate (EMS), 4-nitroquinoline-1-oxide (4NQO), Bleomycin, and Benzo(a)pyrene (BP).

• BMB Reports
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• v.28 no.5
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• pp.427-432
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• 1995

Ganglioside GM3 and sialidase activities in human fetal liver have been investigated. Gangliosides were extracted from fetal livers by the Folch-Suzuki method and analyzed by high-performance thin layer chromatography (HPTLC). GM3 increased, but lactosylceramide (LacCer) decreased predominantly over the developmental stages. Sialidase in human fetal liver was mainly localized in the lysosomal fraction and its activity was high in the earlier stages of development. The optimum pH for this enzyme was 4.3~4.4. Sialidase was more active with the ganglioside mixture than with GM3, sialyllactose or fetuin. Fetal liver sialidase was still active (20% activity) in the presence of 25% methanol. These results suggested that the changes of the ganglioside GM3 and sialidase activity may be involved in the regulation of cell growth in human fetal liver during development.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.313.3-314
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines and other proinflammatory stimuli. It has been known that aberrant up-regulation of COX-2 is associated with resistance to apoptosis. Contrary to the above notion. treatment of MCF10A-ras cells with the anti-tumor agent ET -18-O-$CH_3$ caused increased expression of COX-2 and its mRNA transcript. while inducing apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase. caspase-3 activation, and positive TUNEL staining. (omitted)

• IMMUNE NETWORK
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• v.12 no.6
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• pp.230-239
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• 2012

Activation-induced cytidine deaminase (AID) is an enzyme that is predominantly expressed in germinal center B cells and plays a pivotal role in immunoglobulin class switch recombination and somatic hypermutation for antibody (Ab) maturation. These two genetic processes endow Abs with protective functions against a multitude of antigens (pathogens) during humoral immune responses. In B cells, AID expression is regulated at the level of either transcriptional activation on AID gene loci or post-transcriptional suppression of AID mRNA. Furthermore, AID stabilization and targeting are determined by post-translational modifications and interactions with other cellular/nuclear factors. On the other hand, aberrant expression of AID causes B cell leukemias and lymphomas, including Burkitt's lymphoma caused by c-myc/IgH translocation. AID is also ectopically expressed in T cells and non-immune cells, and triggers point mutations in relevant DNA loci, resulting in tumorigenesis. Here, I review the recent literatures on the function of AID, regulation of AID expression, stability and targeting in B cells, and AID-related tumor formation.

• Biomedical Science Letters
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• v.20 no.3
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• pp.103-110
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• 2014

Matrix metalloproteinases (MMPs), also called matrixins, function in the extracellular environment of cells and degrade both matrix and non-matrix proteins. They are multidomain proteins and their activities are regulated by tissue inhibitor of metalloproteinases (TIMPs). The uncontrolled regulation of MMPs is involved in various pathologic processes, such as tumor invasion, migration, host immune escape, extravasation, angiogenesis, and tumor growth. Especially, matrix metalloproteinase-9 (MMP-9) is one of the metastasis-accelerating genes involved in metastasis of various types of human cancers. Here, we review the member of MMP family and discusses their domain structure and function, enzyme activation, the mechanism of inhibition by TIMPs. In particular, we focus the role of MMP-9 in relation to cancer metastasis.

• Journal of Life Science
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• v.2 no.4
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• pp.232-239
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• 1992

UDP_GlcNAc is metabolized to form vegetative cell wall, cortical peptidoglycans, and outermost layer consisting of galactosamine-6-phosphate ploysaccharide in life cycle of Bacillus megaterium. To obtain a better understanding of the UDP-GlcNAc regulation, we examined the activity of the common first enzyme for the synthesis of nucleotide precursors of peptidoglycans, enoylpyruvate transferase by newly developed method. Both the specific and the total activity decreased after the end of exponential growth followed by and increase from t5 but decreased again parallel to the appearance of the activity of UDP_GlcNAc-4-epimerase. Antibody specificity to anti-transferase IgG and the elution profile on DEAE-Sepharose revealed that B. megaterium has at least two enoylpyruvate transferase isozymes, and UDP_GlcNAc was metabolized to vegetative cell wall and cortical peptidoglycan by each isozme in exponential growth and in sporulation, respectively in life cycle.

• Archives of Pharmacal Research
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• v.26 no.4
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• pp.301-305
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• 2003

Nitric oxide (NO) is an important bioactive agent that mediates a wide variety of physiological and pathophysiological events. NO overproduction by inducible nitric oxide synthase (iNOS) results in severe hypotension and inflammation. This investigation is part of a study to discover new iNOS inhibitors from medicinal plants using a macrophage cell culture system. Two sesquiterpenes (1 and 2) were isolated from Artemisia iwayomogi (Compositae) and were found to inhibit NO synthesis ($IC_{50} 3.64 \mu g/mL and 2.81 \mu$g/mL, respectively) in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Their structures were identified as 3-Ο-methyl-iso-secotanapartholide (1) and iso-secotanapartholide (2). Compounds 1 and 2 inhibited the LPS-induced expression of the iNOS enzyme in the RAW 264.7 cells. The inhibition of NO production via the down regulation of iNOS expression may substantially modulate the inflammatory responses.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.80-80
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines. The presence of oncogenic ras has been associated with sustained induction of COX-2, which confers resistance to apoptosis. Contrary to the above notion, we found that MCF10A-ras cells treated with an anti-tumor agent, ET-18-O-$CH_3$, underwent apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase, pro-caspase 3 activity, and TUNEL staining, while the same treatment caused an increased expression of COX-2 as well as the elevated production of prostaglandin E$_2$(PGE$_2$).(omitted)