SYNTHESIS OF THE LINEAR B TYPE 2 TRISACCHARIDE Galα3Galβ4GlcNAcβOTMSEt,AND COUPLING OF THE CORRESPONDING 2-CARBOXYETHYL β-THIOGLYCOSIDE TO SEPHAROSE

The synthesis of the Linear B type 2 trisaccharide (Galα3Galβ4GlcNAcβOTMSEt) and the corresponding 2-carboxyethyl β-thioglycoside is described, as well as coupling of the latter to Sepharose.     

毛白杨环氧水解酶的异源表达及其在催化拆分手性环氧化物中的应用

对已公布的全基因组进行检索发现,杨树(Populus tomentosa)至少含有24个预测为可溶性环氧水解酶的基因.从中选取了7个可能的环氧水解酶基因进行克隆,通过扩增得到其中5个毛白杨(Populus tomentosa Carr)环氧水解酶基因.序列分析显示,它们与已克隆的巨大芽胞杆菌环氧水解酶的同源性仅为24%～26%.对该系列基因进行了在E.coli中的异源表达,并将得到的5个环氧水解酶(PTEH1～5)用于缩水甘油苯基醚和对硝基苯乙烯氧化物的酶促水解反应.结果发现,其中3个重组酶具有显著的环氧水解酶活性.进一步研究表明,PTEH1和PTEH2对于缩水甘油苯基醚显示了一定的反常规的(R)-选择性,而PTEH5则优先水解(S)-构型的缩水甘油苯基醚.因此,毛白杨中环氧水解酶表现出多样性.     

High-performance liquid chromatographic assay with fluorescence detection for the evaluation of inhibitors against fatty acid amide hydrolase

A fluorescent assay for the evaluation of inhibitors of fatty acid amide hydrolase (FAAH) is described. Microsomes from rat brain served as enzyme source. N-(2-Hydroxyethyl)-4-pyren-1-ylbutanamide was designed and synthesized as novel fluorogenic substrate. For substrate solubilization, Triton X-100 was employed. The FAAH activity was determined directly without further sample clean-up by measuring the amount of 4-pyren-1-ylbutanoic acid released by the enzyme with reversed-phase HPLC and fluorescence detection. The known FAAH inhibitors URB597, phenyl hexanoyl oxazolopyridine (PHOP) and [6-(2-methyl-4,5-diphenyl-1H-imidazol-1-yl)hexyl]carbamic acid phenyl ester were used to validate the test assay.     

Efficient Synthesis of a Water-Soluble Glucoamide Inhibitor Against Human Aldose Reductase by Click Chemistry

While D-glucose is the natural substrate of aldose reductase (AR) in the polyol pathway, the K _m value of D-glucose against AR is large. A glucoamide 1 was designed as a tool to investigate whether AR has a strong affinity for the open form of D-glucose. Glucoamide 1 was synthesized in high yield by modification of the reaction condition for click chemistry. It was found that our modified condition was applicable for highly polar alkynes and gave coupling products in excellent yield (90% to 100%). Although weak inhibitory activity against AR was observed, kinetic studies showed that AR does not accept glucoamide 1 in its active site.