Riboflavin Tetrabutylate가 약물대사 효소 및 지질 과산화효소에 미치는 영향

이향우,김원준,홍사석,곽창열,홍사오 大韓藥理學會 1980 대한약리학잡지 Vol.16 No.2

Lipid peroxidation in vitro has been identified as a basic deteriorative reaction in cellular mechanism of aging processes, such as air pollution oxidant damage to cell and to the lung, chlorinated hydrocarbon hepatotoxicity. Many experimental evidences were reported by several investigators that lipid peroxidation could be one of the principle causes for the hepatotoxicity produced by <TEX>$CCl_4$</TEX>. It is now reasonably established that <TEX>$CCl_4$</TEX> is activated to a free radical in vivo, that lipid peroxidation occurs very quickly in microsomes prepared from damaged livers, that the peroxidation is associated with loss of enzyme activity of microsomes, and that various antioxidants can protect animals against the hepatotoxic effect of <TEX>$CCl_4$</TEX>. Recent studies have drawn attention to some other feature of microsomal lipid peroxidation. Incubation of liver microsomes in the presence of NADPH has led to a loss of cytochrome <TEX>$P_{450}$</TEX>. However, the presence of an antioxidant prevented lipid peroxidation and preserved cytochrome <TEX>$P_{450}$</TEX>. Decrease of cytochrome <TEX>$P_{450}$</TEX> in microsomes under in vitro incubation can be enhanced by <TEX>$CCl_4</TEX> and these changes were parallel to a loss of microsomal polyunsaturated fatty acid and formation of malonaldehyde. The primary purpose of this experiment was to study the effect of riboflavin tetrabutylate on lipid peroxidation, specially, the relationship between lipid peroxidation and drug metabolizing enzyme system which is located in smooth endoplasmic recticulum as well as the effect of ritoflavin tetrabutylate on drug metabolizing enzyme system of animal treated with <TEX>$CCl_4$</TEX>. Albino rats were used for experimental animal. In order to induce drug metabolizing enzyme system, phenobarbital was injected intraperitoneally. <TEX>$CCl_$</TEX> and riboflavin tetrabutylate were given intraperitoneally as solution in olive oil. Microsomal fraction was isolated from

Euglena의 Cytochrome C552 Methylation에 관한 연구

이향우(Hyang Woo Lee),백운기(Woon Ki Paik) 대한약학회 1988 약학회지 Vol.32 No.6

Post-translational modification of protein amino acid residues is a well known metabolic phenomenon. One such side chain modification, protein methylation, occur ubiquitously in nature, in organism ranging from prokaryotic to eukaryotic and the biological significance of protein methylation has begun to emerge. The observation that cytochrome C methylation facilitates the binding of this hemoprotein to mitochondria could be placed as the one of the examples along this line. However, the detail biological meaning of cytochrome C methylation is remained to be clarified. In the aspect of such reason this research was done. The results of this experiment were; 1) pure Euglena gracilis cytochrome C552 was isolated, 2) methylarginine and methylmethionine were not found in cytochrome C552 sequence, 3) however, Unknown Peak at 20.78 min of retention time was found, and 4) this Unknown Peak was found only from Euglena cytochrome C552, so far.

膵臟 組織내 Protein Methylase I 酵素의 精製

李香雨,李晦榮 成均館大學校 科學技術硏究所 1985 論文集 Vol.36 No.1

An enzyme which methylates the guanido group of arginine residues of protein using S-adenosyl-L-methionine as methyl donor has been designated as protein methylase I. Among the enzyme products of this reaction which thus far have been identified are N^G-mono, N^G,N^c-di-, and N^G, N'^G- dimethylarginine. This enzyme is widely distributed in various organs of rat, being especially rich in pancreas of hog. The level of protein methylase I activity was found to closely parallel the rate of cell proliferation. Elevated activity was observed in fetal tissues, continuously dividing HeLa S-3 cell culture, regenerating adult rat liver, and in fast growing Novikoff hepatoma. Protein merhylase I has been purified from calf brain, rat and calf thymus, Krebs II ascites cells and recently a form of protein merhylase I has also been purified from wheat germ, which is the first report of the enzyme being present in the plant kingdom. In the present paper, protein methylase I has been partially purified from hog pancreatic tissue. 1) Protein methylase I has been partially purified about 14-fold from hog pancreatic tissue with 25% yield. 2) Mainly the enzyme was found in cytosolic fraction of pancreatic cells. 3) Main purification steps were homogenation of the tissue, S_3 fraction of cells, 35% ammonium sulfate ppt., and DIEM-cellulose chromatography.

유한요소법을 이용한 승용차 steering column의 3-piece 용접부에 대한 열응력해석

김향우,김옥삼 麗水水産大學校 産業技術硏究所 1996 産業基術硏究所 論文集 Vol.5 No.-

Welding of 3-piece is a important technological method in mechanical engineering. Co₂/MAG(Metal Active Gas) welding means that matal part in steering column of passenger car are joined by melting(with or without a filler material) or that new material is added to a matal part by melting. The welding thermal stresses appear due to a non-uniform temperature field. inhomogeneous material properties, external restraint and volume changes during phase trnsformations. The analysis of thermal stresses may also be possible to avoid some large expensive expriments or experimental parametric studies which can often be made less expensively by numerical simulation. The thermal and mechnical properties of material very with temperature, so that the temperature dependence of material properties must be taken into consideration in the thermal stress analysis of these elements. In this study analysis the thermal stresses distribution of 3-piece welding area in steering column for passenger car using finite element method(FEM). Therefore it calculates the numerical value that can be applied to the optimun design of welding parts and the shapes. The significant results obtained in this study are summerized as follows. At early stage of the cooling, the abrupt thermal stresses gradient has been shown in vicinity of the bottom face of welding area. In the thermal stresses analysis due to temperature gradient and heat shocking maxinum stress was occurred in the top part of welding zone and stresses were distributied from 1950 MPa to -1900 MPa.

타이어공장 근로자 수근관증후군의 업무관련성 조사 사례: 노출평가

류향우(H-W Ryu),박정근(J-K Park),정윤경(Y-K Chung),한영선(Y-S Han),장승희(S-H Chang) 대한인간공학회 2015 대한인간공학회 학술대회논문집 Vol.2015 No.10

주목받는 沮害劑 개발 : 癌?심혈관?백내장치료제등 다양

李香雨 약사공론 1992 대한약사회지 Vol.1992 No.1

방사 및 열처리 조건에 따른 PEN fiber 의 구조 및 물성 변화

노향우,옥영숙,송기봉 한국고분자학회 1996 한국고분자학회 학술대회 연구논문 초록집 Vol.1996 No.10

Blood Compatibility of Hydrophilic Polyurethane and Hydrophobic Polystyrene IPNs

노향우,김성철 한국고분자학회 1994 한국고분자학회 학술대회 연구논문 초록집 Vol.1994 No.10

비타민 A 및 $B_2$ 유도체의 Aminopyrine Demethylase 활성도에 대한 영향

이향우 대한약학회 1984 약학회지 Vol.28 No.1

Drug-metabolizing system which has the important role in drug metabolism is localized in smooth endoplasmic reticulum of hepatocytes and is composed of NADPH, NADPH-cytochrome $P_{450}$ reductase, cytochrome $P_{450}$ and others. It is well known that the enzyme system is induced by phenobarbital and methylcholanthrene. Lipid peroxidation is reaction of oxidative deterioration of polyunsaturated lipids. Formation of lipid peroxides in liver microsome has been found to produce degradation of phospholipid, which are major components of microsomal membrane. The relationship between the formation of lipid oxides and the activities of drug-metabolizing enzyme in the liver of rats was reported by several investigators. In this study the effect of riboflavin tetrabutylate, an antioxidant on lipid peroxidation, specially the relationship between lipid peroxidation and drug-metabolizing enzyme system was investigated. In addition the effect of vitamin A derivatives, such as retinoic acid and retinoid on the enzyme was also observed. Results are summarized as followings. 1) The pretretment with riboflavin tetrabutylate inhibited completely the lengthened sleeping time due to $CCl_{4}$ treatment. 2) The increase of TBA value was prevented by the pretreatment with riboflavin tetrabutylate. 3) The pretreatment with riboflavin tetrabutylate also prevented the decrease of drug-metabolizing enzyme caused by $CCl_{4}$. 4) Both retinoic acid and retinoid remarkably decreased the activity of aminopyrine demethylase. Pretreatment of riboflavin tetrabutylate, however, prevented inhibitory effect of retinoic acid on the enzyme activity.

취외분비에 미치는 cyclic nucleotides의 역할

이향우,김원준,홍사석,Lee, H.W.,Kim, W.J.,Hong, S.S. 대한약리학회 1977 대한약리학잡지 Vol.13 No.2

In 1968, Case et al. first studied the importance of cyclic AMP as an intermediate in the action of secretin and cholecystokinin-pancreozymin and they suggested that the action of secretin, not that of cholecystokinin-pancreozymin, may be mediated through cyclic AMP. Recently Albano et al. reported that in the exocrine pancreas each of the two major physiological functions is modulated a specific cyclic nucleotide, enzyme secretion by cyclic GMP, and fluid and ionic secretion by cyclic AMP. But in pancreas still conflicting results have been reported on the role of cyclic nucleotides in enzyme and electrolyte secretion. In these study, the role of cyclic nucleotides in the exocrine pancreatic secretion was examined. The results are as follows. 1) Very strong stimulation on amylase release from guinea pig pancreatic slice was produced by 1 unit of cholecystokinin-pancreozymin but as compared to that of cholecystokinin-pancreozymin very weak response was observed by 1 unit of secretion or $1\;{\mu}g$ of VIP. 2) Both cholecystokinin-pancreozymin and acetylcholine produced a rapid and marked rise in cyclic GMP as well as cyclic AMP in isolated pancreatic tissue. However, both secretin and VIP failed to alter significantly the basal level of cyclic GMP in pancreatic fragments. 3) Atropine inhibited acetylcholine mediated amylase release, but did not affect the cholecystokinin-pancreozymin response. Furthermore, atropine pretreatment produced a marked inhibitory effect on the increase of tissue cyclic nucleotides induced by cholecystokinin-pancreozymin and acetylcholine. In summary, these results suggest that whereas the pancreatic secretion produced by secretin and VIP is modulated by the formation of cyclic AMP, the pancreatic enzyme secretion in response to cholecystokinin-pancreozymin and acetylcholine is triggered by both cyclic AMP and cyclic GMP.