The recombinants were constructed by transforming ppic9 a - xynb into p. pastoris gs115. the assay results revealed that the xylanase gene xynb was overexpressed and secreted effectually in p. pastoris. in 3l fermentor the expression level of xylanase xynba exceeded 1200iu / ml and the expressed xylanase had normal bioactivity. the molecule weight of xynba was determined as about 31kd which is higher than 23kd of original enzyme xynb from streptomyces olivaceoviridis a1. xynbb was gotten by deglycasylation of xynba, whose molecule weight returned to 23kd. we comparised the enzymatic properties of xynba expressed in p. pastoris, xynbb deglycasylated from xynba and xynb produced from streptomyces olivaceoviridis al : there was little difference among the three enzymes on optimal ph, the optimal ph of xynb and xynba were both 5. 2, the optimal ph of xynbb was 5. 0 ; the optimal temperature of xynb and xynba were both 60 c, while the optimal temperature of xynbb was 50 ? ; because of glycosylation the thermal stability of xynba was better than xynb and xynbb ; the specific activity of xynba and xynbb were 883. 88iu / mg and 832. 5hu / mg respectively, which were both lower than 2814. 45iu / mg of xynb ; the km values of xynb and xynba were similar to each other which were 21. 56 ( g / kg ) and 20. 87 ( g / kg ), while the km value of xynbb was 27. 10 ( g / kg ) ; the fmax of xynba and xynbb were 4568umol / mg. min and 5329umol / mg. min respectively which were lower than 27623 umol / mg. min of xynb ; additionally all of the three enzymes did not display cellulase activity. they all had well resistance to pepsion and trypsin, and were not sensitive to metal iron, surface active agent and chelating agent. the analysis of different xylans enzymatic hydrolysate revealed : by xynba, that the main constitutions of enzymatic hydrolysate of birch wood xylans were xylotriose and xyloquaiose, which account for 68. 43 % and 16. 50 % respectively, additionally there was 11. 79 % of xylobiose ; the main constitutions of enzymatic hydrolysate of corncobs xylans were xylobiose and xylotriose, which account for 81. 78 % and 11. 55 %. the result indicated that this xylanase was a kind of 1, 4 - b - d - xylanohydrolase and was fit to used in industrial procession of xylooligosacc harides
進一步對xynba進行了脫糖
基化處理得到xynbb ,其分子量恢復到23kd ,證明xynba是糖
基化蛋白。通過對畢赤酵母重組表達的木聚糖酶xynba 、脫糖
基化的木聚糖酶xynbb以及橄欖綠鏈黴菌a1所產原酶xynb之間酶學性質的比較發現:三種酶的最適ph差異不大, xynb和xynba均為5 . 2 , xynbb為5 . 0 ; xynb和xynba的最適溫度均為60 , xynbb降為50 :在耐熱性上, xynba由於糖
基化作用熱穩定性明顯高於未糖
基化的xynb和xynbb ; xynba和xynbb的比活性分別為883 . 88iu mg和832 . 51iu mg ,明顯低於原酶的比活2814 . 45iu mg ; xynb和xynba的km值相當,分別為21 . 56 ( g kg )和20 . 87 ( g kg ) ,而xynbb的km值較大為27 . 10 ( g kg ) ; xynba和xynbb的vmax相差不大,分別為4568 mol mg ? min和5329 mol mg ? min ,明顯低於xynb的27623 mol mg ? min此外三種酶均無纖維素酶活性,對胃蛋白酶和胰蛋白酶有很好的抗性,且對作用環境中的各種離子、表面活性劑、
螯合劑不敏感。通過對不同木聚糖的酶解產物的糖份分析發現:以樺木木聚糖為底物時,酶解產物主要為木三糖和木四糖,含量分別為68 . 43和16 . 50 ,另外還含有11 . 79的木二糖;以玉米芯木聚糖為底物時,酶解產物主要為木二糖和木三糖,含量分別為81 . 78和11 . 55 。
Rearrangements have been occurred in at least twelve mitochondrial genes, which have drastically altered the gene order of the mitten crab e. japonica sinensis to the putative ancestral pancrustacean ( crustacean / insecta ) gene order
中華絨
螯蟹線粒體
基因組與推測的泛甲殼類原始的線粒體
基因順序相比,至少有12個
基因發生了重排,造成線粒體
基因排列順序顯著的變化。
2. the sox gene expression analysis of different tissues from eriocheir sinensis was studied by using rt - pcr
2 、採用rt ? pcr技術,研究了中華絨
螯蟹精巢、卵巢、心臟、肌肉四種組織中sox
基因的表達。
Recent development of absorption and separation materials with amidoxime group
偕胺肟
基螯合吸附分離材料研究進展
Both the frequency and intensity of 1146. 0cm - 1 change largely, etc. discussed and compared the mechanism of these interaction in detail we got some conclusions as following : both zn2 + and cd2 + ions can chelate with po2 - and come into being - po2 - me2 + n7 ( purine ) chelate. as to zn2 + ions, when r2. 0, the quantity of po2 - zn2 + n7 is directly linear with r. when r2. 0, zn2 + ions even can chelate with c at n3 - o2 sites and this chelation will disrupt the h - bond between gc base pairs and make the dna structure unstable. as to cd2 + ions, only when r is within 1. 0 - 1. 5 can this chelation take place and the relation of the quantity of this chelate with r is not easy to conclude
通過對這些變化進行詳細討論和分析,我們得到了如下的結論: zn ~ ( 2 + )和cd ~ ( 2 + )都可以跟dna的磷酸
基團
螯合,形成- po _ 2 ~ - … me ~ ( 2 + ) … n7 ( g )
螯合物,但是前者的
螯合跟離子濃度有很大的關系,在摩爾濃度比小於2 . 0時,
螯合物的生成量跟r成正比關系,而後者的
螯合跟離子的關系不是很明顯,只有當r處於1 . 0至1 . 5之間時,
螯合作用才能進行,並且
螯合物的生成量跟r之間沒有很明顯的關系存在。
Chelate reaction between borate ions and phenol hydroxyl group, ortho - position hydroxymethyl group of phenol - formaldehyde resol resin
硼酸根與甲階酚醛樹脂中酚羥
基和鄰位羥甲
基的
螯合反應
Application and exploit of the feed additive of compound amino acid chelated mineral element
復合氨
基酸微量元素
螯合物飼料添加劑的應用與開發
Microelement amino acid chelate is a newly additive, which was studied extensively, and the nutritional function of microelement amino acid was confirmed by many studies. but the study of copper amino acid chelate was seldom. in this study, mice were used as animal model, cu - lys and cu - met were studied as representative of copper amino acid chelate
微量元素氨
基酸
螯合物是現今研究最廣泛的新型微量元素添加劑,其優秀的營養作用已為眾多的添加效果試驗所證實,但有關氨
基酸
螯合銅的研究報道較少,本課題以小鼠為動物模型,以賴氨酸整合銅和蛋氨酸
螯合銅為代表進行了以下3部分試驗,研究飼糧銅源和銅水平對小鼠銅營養狀況及免疫功能的影響。
The purposes of this project were to further analyze the characteristics of their iron efficiency under iron stress, to study the physiological and molecular mechanisms of iron efficiency under iron deficiency in c. junos and m. xiaojinensis, and to analyze the spatial expression model of fcr ( ferric chelate reductase ) gene under iron stress with the hope to cast a new light on iron stress tolerance on the molecular level, to lay solid foundations for cloning fcr gene in c. junos and m. xiaojinensis, and to provide some basic data for creating new rootstocks with excellent complex characters and iron efficiency
本研究通過進一步分析香橙和小金海棠的耐缺鐵特性,研究它們耐缺鐵的生理原因和分子
基礎,並通過分析三價鐵
螯合物還原酶
基因的空間表達模式,從分子水平上去探討植物耐缺鐵的原因,為從香橙和小金海棠中克隆三價鐵
螯合物還原酶
基因奠定
基礎,並為人工創造耐缺鐵的果樹砧木提供
基礎研究數據。
Research and preparation of a new chelating fiber containing thioamide group
一種硫代酰胺
基螯合功能纖維的研製
On the base of these, we studied the effect of chelator on the stability of acidic juice - milk
在此
基礎上,研究
螯合劑對調酸果奶穩定性的影響。
These can include animal - based, cell culture - based, biochemical, or ligand / receptor - binding assays
這些分析方法可以包括基於動物的,細胞培養的,生物化學的或配位體/接受體螯合的分析方法。