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Jae Hoon Bahn,A Yeon Kim,장상호,Byung Ryong Lee,Jee-Yin Ahn,Hye Mee Joo,강태천,원무호,Hyeok Yil Kwon,Jung Hoon Kang,Oh-Shin Kwon,Hyong Bai Kim,조성우,Kil Soo Lee,Jinseu Park,최수영 한국분자세포생물학회 2002 Molecules and cells Vol.13 No.1
Five monoclonal antibodies that recognize porcine brain myo-inositol monophosphate phosphatase (IMPase) have been selected and designated as mAb IMPP 9, IMPP 10, IMPP 11, IMPP 15, and IMPP 17. These antibodies recognize different epitopes of the enzyme and one of these inhibited the enzyme activity. When the total proteins of the porcine brain homogenate separated by SDS-PAGE were probed with monoclonal antibodies, a single reactive protein band of 29 kDa, co-migrating with the purified porcine brain IMPase, was detected. Using the anti-IMPase antibodies as probes, the cross reactivities of the brain IMPase from human and other mammalian tissues, as well as from avian sources, were investigated. Among the human and animal tissues tested, the immunoreactive bands on Western blots appeared to have the same molecular mass of 29 kDa. In addition, there was IMPase immunoreactivity in the various neuronal populations in the rat brain. These results indicate that mammalian brains contain only one major type of immunologically similar IMPase, although some properties of the enzymes that were previously reported differ from each another. The first demonstration of the IMPase localization in the brain may also provide useful data for future investigations on the function of this enzyme in relation to various neurological diseases.
Different Antigenic Reactivities of Bovine Brain Glutamate Dehydrogenase Isoproteins
Bahn, Jae Hoon,Choi, Soo Young,Hong, Joung Woo,Lee, Byung Ryong,Ahn, Jee-Yin,Jeon, Seong Kyu,Song, Min-Sun,Cho, Sung-Woo 한림대학교 부설 환경ㆍ생명과학연구소 1999 일송 의학ㆍ생명과학 심포지엄 Vol.- No.1
The structural differences between two types of glutamate degydrogenase (GDH) isoproteins (GDH Ⅰ and GDH Ⅱ), homogeneously isolated from bovine brain, were investigated using a biosensor technology and monoclonal antibodies A total of seven monoclonal antibodies raised against GDH Ⅱ were produced, and the anitbodies recognized a single protein band that comigrates with purified GDH Ⅱ on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot. Of seven anti-GDH Ⅱ monoclonal antibodies tested in the immunoblot analysis, all seven antibodies interacted with GDH Ⅱ, whereas only four antibodies recognized the protein band of the other GDH isoprotein, GDH Ⅰ. When inhibition tests of the GDH isoproteins were performed with the seven anti-GDH Ⅱ monoclonal antibodies, three antibodies inhibited GDH Ⅱ activity, whereas only one antibody inhibited GDH Ⅰ activity. The binding affinity of anit-GDH Ⅱ monoclonal antibodies for GDH Ⅱ(Kp=1.0 nM) determined using a biosensor technology (Pharmacia BIAcore) was fivefold higher than for GDH Ⅰ(Kp=5.3nM). These results, together with epitope mapping analysis, suggest that there may be structural differences between the two GDH isoproteins, in addition to their defferent biochemical properties. Using the anti-GDH Ⅱ antibodies as probes, we also investigated the crossreactivities of brain GDHs from some mammalian and an avian species, showing that the mammalian brain GDH enzymes are related immunologically to each other.
Bahn, Jae-Hoon,Lee, Byung-Ryong,Jeon, Seong-Gyu,Jang, Joong-Sik,Kim, Chung-Kwon,Jin, Li-Hua,Park, Jin-Seu,Cho, Yong-Joon,Cho, Sung-Woo,Kwon, Oh-Shin,Choi, Soo-Young Korean Society for Biochemistry and Molecular Biol 2000 Journal of biochemistry and molecular biology Vol.33 No.4
The succinic semialdehyde dehydrogenase from bovine brain was inactivated by treatment with phenylglyoxal, a reagent that specifically modifies arginine residues. The inhibition at various phenylglyoxal concentrations shows pseudo-first-order kinetics with an apparent secondorder rate constant of 30 $M^{-1}min^{-1}$ for inactivation. Partial protection against inactivation was provided by the coenzyme $NAD^+$, but not by the substrate succinic semialdehyde. Spectrophotometric studies indicated that complete inactivation of the enzyme resulted from the binding of 2 mol phenylglyoxal per mol of enzyme. These results suggest that essential arginine residues, located at or near the coenzyme-binding site, are connected with the catalytic activity of brain succinic semialdehyde dehydrogenase.
Bahn, Gahee,Park, Jong-Sung,Yun, Ui Jeong,Lee, Yoon Jee,Choi, Yuri,Park, Jin Su,Baek, Seung Hyun,Choi, Bo Youn,Cho, Yoon Suk,Kim, Hark Kyun,Han, Jihoon,Sul, Jae Hoon,Baik, Sang-Ha,Lim, Jinhwan,Wakabay National Academy of Sciences 2019 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.116 No.25
<P><B>Significance</B></P><P>Considering that Alzheimer’s disease (AD) is a chronic disease progressing over a long period of time, even a slight increase of <I>BACE1</I> expression may have a profound effect on Aβ accumulation. We describe a previously unknown mechanism that negatively regulates <I>BACE1</I> and <I>BACE1-AS</I> expression and demonstrate its pivotal role in the progression of Aβ and Tau pathologies and cognitive impairment in two mouse models of AD. Given the recent failures of the clinical trials using enzymatic inhibitors of BACE1, it is critical to explore alternative approaches such as down-regulating <I>BACE1</I> and <I>BACE1-AS</I> transcription. Our finding that NRF2 negatively regulates BACE1 and BACE1-AS therefore suggests a potential for disease modification by NRF2-activating phytochemicals or synthetic small molecules in AD.</P><P>BACE1 is the rate-limiting enzyme for amyloid-β peptides (Aβ) generation, a key event in the pathogenesis of Alzheimer’s disease (AD). By an unknown mechanism, levels of <I>BACE1</I> and a <I>BACE1</I> mRNA-stabilizing antisense RNA (<I>BACE1-AS</I>) are elevated in the brains of AD patients, implicating that dysregulation of <I>BACE1</I> expression plays an important role in AD pathogenesis. We found that nuclear factor erythroid-derived 2-related factor 2 (NRF2/NFE2L2) represses the expression of <I>BACE1</I> and <I>BACE1-AS</I> through binding to antioxidant response elements (AREs) in their promoters of mouse and human. NRF2-mediated inhibition of <I>BACE1</I> and <I>BACE1-AS</I> expression is independent of redox regulation. NRF2 activation decreases production of <I>BACE1</I> and <I>BACE1-AS</I> transcripts and Aβ production and ameliorates cognitive deficits in animal models of AD. Depletion of NRF2 increases <I>BACE1</I> and <I>BACE1-AS</I> expression and Aβ production and worsens cognitive deficits. Our findings suggest that activation of NRF2 can prevent a key early pathogenic process in AD.</P>
Chemical Modification of Porcine Brain myo-Inositol Monophosphate Phosphatase by N-bromosuccinimide
Lee, Byung-Ryong,Bahn, Jae-Hoon,Jeon, Seong-Gyu,Ahn, Yoon-Kyung,Yoon, Byung-Hak,Kwon, Hyeok-Yil,Kwon, Oh-Shin,Choi, Soo-Young Korean Society for Biochemistry and Molecular Biol 1999 Journal of biochemistry and molecular biology Vol.32 No.3
Myo-inositol monophosphate phosphatase is a key enzyme in the phosphoinositide cell-signaling system. Incubation of myo-inositol monophosphate phosphatase from porcine brain with N-bromosuccinimide (NBS) resulted in a time-dependent loss of enzyme activity. The inactivation followed pseudo-first-order kinetics with the second-order rate constant of $3.8{\times}10^3\;M^{-1}min^{-1}$. The time course of the reaction was significantly affected by the substrate myo-inositol-1-phosphate, which afforded complete protection against the loss of catalytic activity. Spectrophotometric studies indicated that about one oxindole group per molecule of enzyme was formed following complete loss of enzymatic activity. It is suggested that the catalytic function of myo-inositol monophosphate phosphatase is modulated by the binding of NBS to a specific tryptophan residue at or near the substrate binding site of the enzyme.
Choi, Soo Young,Bahn, Jae Hoon,Park, Jinseu,Jin, Li Hua,Lee, Byung Ryong,Kim, Chung Kwon,Cho, Sung-Woo,Jeon, Seong Gyu,Cho, Yong Joon,Jang, Joong Sik,Kwon, Oh-Shin The Korea Science and Technology Center 2000 BMB Reports Vol.33 No.4
The succinic semialdehyde dehydrogenase from bovine brain was inactivated by treatment with phenylglyoxal, a reagent that specifically modifies arginine residues. The inhibition at various phenylglyoxal ocncentrations shows pseudo-first-order kinetics with an apparent second-order rate constant of 30 M-¹min-¹ for inactivation. Partial pretection against inactivation was provided by the coenzyme NAD+, but not by the substrate succinic semialdehyde. Spectrophotoetric studies indicated that complete inactivation of the enzyme resulted from the binding of 2 mol phenylglyoxal per mol of enzyme. These results suggest that essential arginine residues, located at or near the coenzyme-bindig site, are connected with the catalytic activity of brain succinic semialdehyde dehydrogenase.
Stimulatory Effects of Ginsenosides on Bovine Brain Glutamate Decarboxylase
Choi, Soo-Young,Bahn, Jae-Hoon,Jeon, Seong-Gyu,Chung, Young-Mee,Hong, Joung-Woo,Ahn, Jee-Yin,LeeHwang, EunJoo,Cho, Sung-Woo,Park, Jin-Kyu,Baek, Nam-In The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.3
A GABA synthesizing enzyme, glutamate decarboxylase, has been purified from bovine brain by several chromatographic procedures. The preparation appeared homogeneous on SDS-PAGE. The enzyme is a homodimeric protein with a molecular mass of 120 kDa. The activation of glutamate decarboxylase by ginesenosides from Panax ginseng C.A. Meyer has been studied. Preincubation of the enzyme with total ginsenoside, Rb₂and Rc ginsenosides, increased glutamate decarboxylase activities in a dose-dependent manner. There was a reproducible decrease in Km, in addition to a increase in Vmax, in response to increasing concentrations of the Rc ginsenoside fraction. Upon addition of the ginsenoside to the enzyme, a decrease in flurorescence intensity was discernible, together with an increase in emission anisotropy. Judging from the anisotropy values, the ginsenoside is rapidly trapped by the protein matrix. Total ginsenoside was administered to rats and the rat brains were removed for the measurement of the changes of GABA shunt regulating enzyme activities. Among the GABA shunt regulating enzymes, only the glutamate decarboxylase activities were increased after ginsenoside treatment. Therefore, it is suggested that the ginsenosides may elevate the GABA level in brain by activation of glutamate decarboxylase and the enzymatic activation might be due to the conformational change induced by binding of ginsenoside to the enzyme.