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김영식,황성오,최경훈,안무업,오중환,임경수,윤정환,강성준 大韓應急醫學會 1992 대한응급의학회지 Vol.3 No.1
To evaluate the physiologic extent of pulmonary contusion and effect of PEEP therapy for pulmonary contusion, we studied 16 patients received PEEP therapy with pulmonary contusion from nonpenetrating chest trauma. Hemodynamic parameters including pulmonary vascular resistance index and intrapulmonary shunt fraction were calculated from standard measurement, and arterial oxygen tension was measured. Pulmonary vascular resistance index and intrapulmonary shunt fraction were increased in patient group. Arterial oxygen tension was decreased with increase of the intrapulmonary shunt fraction(R=0.75). Arter minimal PEEP therap(5-10 ㎝H₂O), pulmonary vascular resistance index was remained unchanged and intrapulmonary shunt fraction was decreased without significant changes of pulmonary hemodynamics. Increment of arterial tension was increased with decrease of intrapulmonary shunt fraction(R=0.43). Decreased stroke volume index suggested of cardiac injury such as cardiac contusion in patient group. These results of our study suggested that increased intrapulmonary shunt fraction caused arterial hypoxia in pulmonary contusion and arterial oxygen tension was increased as a result of reduced intrapulmonary shunt by PEEP therapy.
( Joong Hoon Ahn ),( Bong Gyu Kim ),( You Hoon Chong ),( Byoung Chan Ahn ),( Eun Ji Joe ),( Jun Cheol Park ),( Jung Na Ri ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.10
The attachment of sugar to flavonoids enhances their solubility. Glycosylation is performed primarily by uridine diphosphate-dependent glycosyltransferases (UGTs). The UGT from Bacillus cereus, BcGT-1, transferred three glucose molecules into kaempferol. The structural analysis of BcGT-1 showed that its substrate binding site is wider than that of plant flavonoid monoglucosyltransferases. In order to create monoglucosyltransferase from BcGT-1, the error-prone polymerase chain reaction (PCR) was performed. We analyzed 150 clones. Among them, two mutants generated only kaempferol O-monoglucoside, albeit with reduced reactivity. Unexpectedly, the two mutants harbored mutations in the amino acids located outside of the active sites. Based on the modeled structure of BcGT-1, it was proposed that the local change in the secondary structure of BcGT-1 caused the alteration of triglucosyltransferase into monoglucosyltransferase.
Ahn, Joong Hoon,Hwang, Jin Bong,Kim, Seung Ho 한국산업미생물학회 1991 한국미생물·생명공학회지 Vol.19 No.4
Ethylene glycol, glycerol, sorbitol 그리고 sucrose가 Bacillus stearothermophilus가 생산하는 cyclodextrin glucanotransferase(CGTase)의 열안정성에 미치는 영향을 조사하였다. Glycerol, sorbitol 그리고 sucrose가 CGTast의 열안정성에 효과가 있었다. 이 효과는 첨가물의 농도와 밀접한 관계가 있었다. n-Butanol, 1,4-dioxane 그리고 n-octane과 같은 유기 용매에서 CGTase의 열안정성을 조사하였다. 1,4-dioxane과 n-octane은 CGTase의 열안정성을 증가시켰다. 특히, n-octane에서 CGtase를 75℃에서 90분간 정치시킨 후에도 원래 효소활성의 81%를 유지하였다. The influence of ethylene glycol, glycerol, sorbitol and sucrose on the thermostability of Bacilus stearothermophilus cyclodextrin glucanotransferase (CGTase ) was investigated. Glycerol, sorbitol and sucrose had effect on thermostability of the CGTase. The effects appeared to be strongly dependent on concentration of additives. The thermostability of CGTase also was assayed in organic solvents such as n-butanol, 1,4-dioxane, n-octane. The thermostability of CGTase increased in 1,4-dioxane and n-octane. Particularly, in n-octane, the CGTase retained the 81% of the initial activity after incubation at 75℃ for 90 min.
Glycosyltransferases from plants; sugar donor/acceptor selection
Joong-Hoon Ahn,Jung Na Ri,Kim Bong Gyu 한국당과학회 2009 한국당과학회 학술대회 Vol.2009 No.1
Glycosylation of plant secondary metabolites is mediated by family 1 glycosyltransferase, called uridine-diphosphate (UDP)-dependent glycosyltransferase (UGT). The N-terminal of UGT recognizes the sugar acceptor and the C-terminal interacts with the sugar-donor. Molecular basis of selection of sugar donor in UGT is not clear. UGT78D2 from Arabidopsis thaliana (AtUGT78D2) transfers a glucose group of UDP-glucose to 3-hydroxyl group of quercetin. On the other hand, the other UGT (ATUGT78D3), which showed 80 % amino acid identity to AtUGT78D2, uses UDP-arabinose as a sugar donor to make quercetin 3-O-arabinodise. Analysis of sugar binding site reveals that five amino acids are different between two UGTs. To find out which amino acid affects to their UDP-sugar donor selectivity, site-directed mutagenesis was performed. One amino acid at the C-terminal of AtUGT78D3 turned out to be critical for the selectionof UDP-sugar. With modeled structures of two AtUGT followed by site-directed mutagenesis, structural basis of UDP-selectivity in UDP-dependent glycosyltransferase is elucidated. Alternation of regioselectivity of UGTs is also challenging area. In order to alter the regioselelctivity, PGT-3 was used. PGTs uses quercetin as substrate and transferrs a glucose to the 4’ hydroxyl group. However, PGT-3 transferred a glucose group to the 3-hydroxyl group of isorhamnetin. Molecular modeling and docking and site directed mutagenesis were carried out to engineer a PGT-3 having a specificity for isorhamnetin but not for quercetin. The engineered PGT-3 that have exclusive activity toward isorhamnetin will be described.