The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus impro...The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and proteins.However,its use is largely precluded by the limited Hmb’s installation sites.In this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of Hmb.The iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to 76-residue.Furthermore,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein sarcolipin.The iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.展开更多
A synthesis of methyl 2-hydroxy-4-oxo-4-（substituted phenyl）butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride. The key feature of this strategy i...A synthesis of methyl 2-hydroxy-4-oxo-4-（substituted phenyl）butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride. The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently, which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.？2009 Yong Sup Lee. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The electrochemiluminescence (ECL) of a new reagent 6- (2-hydroxy- 4 diethy laminophenylazo)-2,3-dihydro-1 ,4-phthalazine-1,4-dione (HDEA) in a basic aqueous so lution was studied by using the apparatus designed by ou...The electrochemiluminescence (ECL) of a new reagent 6- (2-hydroxy- 4 diethy laminophenylazo)-2,3-dihydro-1 ,4-phthalazine-1,4-dione (HDEA) in a basic aqueous so lution was studied by using the apparatus designed by ourselves. Trace amounts of silver ( Ⅰ ) shows a significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the solution. The linear relationship between the light intensity and the concentration of silver( Ⅰ ) occurs in the range of 5. 0×10-8 to 3. 0×10-8 mol/L Ag(Ⅰ ) in a medium of KOH-KCl-HDEA (pH= 12. 8). The detection limit of the method is 2. 0×10-8 mol/LAg( Ⅰ ), and the r. s. d. for 1.0×10-7 mo)/L Ag ( Ⅰ ) is 5%. Of 21 metal ions concerned, only nickel( Ⅱ ), cerium( Ⅳ ) and cobalt( Ⅱ ) interfere the silver detection seriously; Ⅰ and Br also have some interference.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFA0706900)the National Natural Science Foundation of China(Nos.22022703 and 22177108)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP013).
文摘The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and proteins.However,its use is largely precluded by the limited Hmb’s installation sites.In this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of Hmb.The iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to 76-residue.Furthermore,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein sarcolipin.The iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.
基金supported by the Seoul Research and Business Development Program(No.10524).One of theauthors M.N.A.Khan is a recipient of Post-Doctoral fellowship from the post-BK2 1 program,Korea.
文摘A synthesis of methyl 2-hydroxy-4-oxo-4-（substituted phenyl）butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride. The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently, which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.？2009 Yong Sup Lee. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘The electrochemiluminescence (ECL) of a new reagent 6- (2-hydroxy- 4 diethy laminophenylazo)-2,3-dihydro-1 ,4-phthalazine-1,4-dione (HDEA) in a basic aqueous so lution was studied by using the apparatus designed by ourselves. Trace amounts of silver ( Ⅰ ) shows a significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the solution. The linear relationship between the light intensity and the concentration of silver( Ⅰ ) occurs in the range of 5. 0×10-8 to 3. 0×10-8 mol/L Ag(Ⅰ ) in a medium of KOH-KCl-HDEA (pH= 12. 8). The detection limit of the method is 2. 0×10-8 mol/LAg( Ⅰ ), and the r. s. d. for 1.0×10-7 mo)/L Ag ( Ⅰ ) is 5%. Of 21 metal ions concerned, only nickel( Ⅱ ), cerium( Ⅳ ) and cobalt( Ⅱ ) interfere the silver detection seriously; Ⅰ and Br also have some interference.
文摘目的探究枸杞多糖(Lycium barbarum polysaccharides,LBP)调控核因子E2相关因子2(nuclear factor E2 related factor 2,Nrf2)/谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)通路对缺氧/复氧(hypoxia/reoxygenation,H/R)诱导的心肌细胞铁死亡的影响。方法设置对照组、模型组及LBP低、中、高剂量(25、50、100 mg/L)组和LBP(100mg/L)+Nrf2抑制剂ML385(5μmol/L)组。构建H9c2细胞H/R模型,并给予相应药物处理。采用CCK-8检测细胞活力;采用TUNEL染色检测细胞凋亡;采用试剂盒检测细胞Fe^(2+)、谷胱甘肽(glutathione,GSH)、丙二醛(malondialdehyde,MDA)水平及乳酸脱氢酶(lactate dehydrogenase,LDH)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)活性;采用二氢乙锭(dihydroethidium,DHE)荧光探针检测细胞活性氧(reactive oxygen species,ROS)水平;采用透射电镜观察细胞线粒体形态;采用Western blotting检测转铁蛋白受体1(transferrin receptor 1,Tf R1)、二价金属离子转运蛋白1(divalent metal transporter 1,DMT1)、铁蛋白重链1(ferritin heavy chain 1,FTH1)、酰基辅酶A合成酶长链家族成员4(acyl-CoA synthetase long-chain family member 4,ACSL4)、Kelch样ECH相关蛋白1(Kelch like ECH associated protein1,Keap1)、Nrf2、血红素氧合酶-1(heme oxygenase-1,HO-1)、溶质载体家族7成员11(solute carrier family 7 member 11,SLC7A11)、GPX4蛋白表达。结果与对照组比较,模型组细胞活力显著降低(P<0.001),Fe^(2+)、MDA、ROS水平和LDH活性显著升高(P<0.001),GSH水平和SOD、CAT活性显著降低(P<0.001),线粒体缩短、膜密度增高且嵴数量减少,TfR1、Nrf2、HO-1、SLC7A11、GPX4蛋白表达水平显著降低(P<0.001),DMT1、FTH1、ACSL4、Keap1蛋白表达水平显著升高(P<0.001)。与模型组比较,LBP组细胞活力显著升高(P<0.01),Fe^(2+)、MDA、ROS水平和LDH活性显著降低(P<0.05、0.01、0.001),GSH水平和SOD、CAT活性显著升高(P<0.05、0.01、0.001),线粒体形态较为规则,TfR1、Nrf2、HO-1、SLC7A11、GPX4蛋白表达水平显著升高(P<0.01、0.001),DMT1、FTH1、ACSL4、Keap1蛋白表达水平显著降低(P<0.05、0.01、0.001);而ML385能够抑制枸杞多糖对细胞铁死亡的改善作用(P<0.05、0.01、0.001)。结论枸杞多糖可能通过激活Nrf2/GPX4通路改善H/R诱导的心肌细胞铁死亡。
