碱性蛋白酶水解猪血细胞最优反应条件的研究   总被引：14，自引：0，他引：14  

孟祥晨  杨同舟 《东北农业大学学报》1998,29(2):173-178

研究旨在确立碱性蛋白酶水解猪血细胞的最优反应条件。采用二次旋转正交回归设计,建立了ｐＨ值、温度（Ｔ）、酶—底物浓度比（〔Ｅ〕／〔Ｓ〕）三个因素对水解蛋白收率影响的回归模型。通过分析,确定最优水解条件为：ｐＨ＝８２１,〔Ｅ〕／〔Ｓ〕＝４％,最后,在此最优水解条件下,确定出最佳水解时间ｔ＝９０ｍｉｎ。  相似文献   

中国明对虾Kazal型丝氨酸蛋白酶抑制剂基因(Fc-Kazal)的重组表达及活性分析     

黄明  刘逸尘  张亦陈  孙妍  孙金生 《水产学报》2011,35(9):1310-1319

Kazal型丝氨酸蛋白酶抑制剂可以通过精确调控丝氨酸蛋白酶的活力,在生物体的防御应答等众多生物过程中发挥重要作用。以前期克隆的中国明对虾Kazal型丝氨酸蛋白酶抑制剂基因(Fc-Kazal, GenBank注册号为DQ318856)为基础,对其功能结构域进行序列比对和进化分析;组织表达分析结果表明,该基因在血细胞、鳃和淋巴器官等组织中高水平表达,而在眼柄、神经和肌肉中无表达;利用原核表达系统对该基因成熟肽区域成功进行了重组表达,纯化后的目的蛋白最终得率为0.4 g/L培养液;活性分析结果显示,复性后的rFc-Kazal对鳗弧菌、金黄色葡萄球菌、杀鲑气单胞菌、苏云金芽孢杆菌有明显的抑菌作用。  相似文献   

Amino acid uptake by Saccharomyces cerevisiae during ethanol production     

David B. Johnston  Ryan J. Stoklosa 《Cereal Chemistry》2024,101(1):64-72

  相似文献   

Ontogenic changes in the digestive enzyme patterns and characterization of proteases in Indian major carp Cirrhinus mrigala     

R. CHAKRABARTI  R.M. RATHORE 《Aquaculture Nutrition》2010,16(6):569-581

Digestive enzymes of Cirrhinus mrigala (Ham.) were studied during ontogenic development. Specific amylase activity was detected in first feeding fish. The enzyme activity decreased up to day‐18 and then it increased with the age of fish to reach the highest level on day‐34. Protease activity was 28.61 ± 8.90 mU mg protein^?1 min^?1 on day‐4 and increased with the age throughout the study period. Trypsin activity was 31.86 ± 1.12 mU mg protein^?1 min^?1 on day‐4. The activity decreased up to day‐10 and from day‐12 onwards increased up to day‐26. Chymotrypsin activity was 14.56 ± 2.74 mU mg protein^?1 min^?1on day‐4 and constantly increased up to day‐26. A significant increase in lipase activity was observed between days‐24 and 34. SDS‐PAGE and substrate SDS‐PAGE showed the diversity of protein (17.4–127.8 kDa) and protease activity bands (16.6–88.8 kDa) during ontogenesis. Soybean trypsin inhibitor, phenyl methyl sulphonyl fluoride, N‐α‐p‐tosyl‐l ‐lysine chloromethylketone and N‐tosyl‐l ‐phenylalanine chloromethylketone inhibited the protease activity up to 79.72–97.21, 65.55–94.83, 45.41–75.31 and 40.78–64.72%, respectively. Inhibition study in substrate SDS‐PAGE revealed the abundance of serine proteases and the presence of isoforms of trypsin and chymotrypsin. Ethylenediamine‐tetraacetate showed 5.56–22.78% inhibition of metal ion‐specific enzyme activity.  相似文献   

Beneficial effects of dietary exogenous protease on the growth,intestinal health and immunity of GIFT (Oreochromis niloticus) fed plant‐based diets     

Jian‐Jun Wu  Wei Liu  Ming Jiang  Ying Zhou  Wei‐Min Wang  Hua Wen  Hong Liu 《Aquaculture Nutrition》2020,26(5):1822-1834

This study investigated the effects of dietary exogenous protease on the growth performance, intestinal health, immune parameters and disease resistance of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Five test diets with commercial protease at the levels of 0, 1.38, 2.76, 5.52 and 11.04 U/g (named PE0, PE1, PE2, PE5 and PE11, respectively) were administered to triplicate tanks with 30 fish for 60 days, and then, the fish were challenged with Streptococcus agalactiae for 14 days. The results indicated that weight gain increased as exogenous protease increased from 0 to 5.52 U protease/g diet and then decreased significantly (p < .05) with a further increase in exogenous protease supplementation (p < .05). The height of the villi in the proximal intestine and distal intestine, the width of the villi in three segments of the intestine, and the thickness of the muscle layer in the proximal intestine and mid‐intestine (p < .05) were increased in the fish fed the PE5 diet. Immune and antioxidant indices (except malondialdehyde), and survival after challenged with S. agalactiae were higher in fish fed PE5 diets than in those fed other diets (p < .05). In conclusion, 5.52 U/g protease supplementation in a plant‐based diet could promote the growth performance, intestinal physical barrier function, innate immunity and S. agalactiae resistance of GIFT.  相似文献   

Effects of Manipulation of Proteases on Myofibril Protein Degradation of Tilapia Muscle in vitro and in vivo     

Hui Huang  Yanfu He  Xianqing Yang 《Journal Of Aquatic Food Product Technology》2019,28(6):658-666

This study investigated the role of three proteases in myofibril degradation. Tilapia muscle was soaked in MDL-28170, E-64, and AC-DEVD-CHO, specific inhibitors of calpain, cathepsin, and caspase, respectively, for 14 days to determine the in vivo degradation of myofibril. Desmin and troponin T were significantly inhibited after treatment with inhibitors compared to the control (p < .05). For in vitro analyses, myofibril was incubated with recombinant active μ-calpain, cathepsin B, and caspase-3. Desmin was significantly reduced when incubated with recombinant proteases (p < .05). However, troponin T showed significant degradation only in the μ-calpain and cathepsin B treatment groups (p < .05). Our results reveal μ-calpain and cathespin B have similar degradation patterns, while caspase-3 has partly similar degradation for myofibril in vivo and in vitro. This suggests that μ-calpain and cathespin B are the main proteases responsible for post-mortem myofibril degradation, while caspase-3 is minor.  相似文献   

Cry1Ac毒素对小菜蛾幼虫中肠蛋白酶和羧酸酯酶活性的影响     

赵爱平  展恩玲  孙聪  刘同先  李怡萍 《植物保护学报》2017,44(5):713-720

为了明确Cry1Ac毒素对小菜蛾Plutella xylostella幼虫中肠蛋白酶和羧酸酯酶活性的影响,利用蛋白酶专性底物测定其中肠各蛋白酶活性在不同缓冲液中的最适pH,并用不同浓度Cry1Ac毒素饲喂小菜蛾幼虫后测定该毒素的致死中浓度LC_(50),观察中肠蛋白酶和羧酸酯酶活性的变化,分析Cry1Ac毒素与昆虫中肠酶活性间的关系。结果表明,小菜蛾幼虫中肠总蛋白酶在Tris-HCl、KH_2PO_4/NaOH和Glycine/NaOH三种缓冲液中最适pH均为11.0;强碱性胰蛋白酶的最适pH分别为10.0、10.5和10.5;弱碱性胰蛋白酶的最适pH均为8.5;胰凝乳蛋白酶的最适pH分别为8.5、9.0和9.0。Cry1Ac毒素对小菜蛾的致死中浓度LC_(50)为0.343μg/mL。用不同浓度Cry1Ac毒素饲喂小菜蛾幼虫后,其中肠各蛋白酶活性均随时间的变化而变化。弱碱性胰蛋白酶和胰凝乳蛋白酶的活性明显升高,且随浓度升高呈上升趋势;在取食36~72 h期间低浓度处理组的羧酸酯酶活性与对照组间无显著差异,而高浓度处理组羧酸酯酶活性显著高于对照组。表明Cry1Ac毒素能够显著影响小菜蛾的中肠蛋白酶和羧酸酯酶活性。  相似文献   

不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响   总被引：2，自引：1，他引：1  

高攀  蒋明  文华  赵宇江  吴凡  刘伟 《淡水渔业》2009,39(6)

以鱼粉和豆粕为蛋白源,鱼油和豆油等比例混合油为脂肪源,共配制4个蛋白水平(20%、25%、30%、35%),每一蛋白水平设4个脂肪水平(4.5%、8%、11.5%、15%),共16组饲料。每组设3个重复,在水温23~29℃下,连续投喂初始体重为(16.84±0.28)g的草鱼(Ctenopharyngodon idellus)10周,研究不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响。结果显示:肠道蛋白酶的活性随着饲料蛋白含量的升高而显著升高(P<0.05),饲料蛋白水平在20%~30%时,饲料中的脂肪水平对蛋白酶活性影响不显著(P>0.05),蛋白水平在35%时,高脂肪抑制了蛋白酶活性,肝胰脏的蛋白酶变化规律类似于肠道;肠道和肝胰脏淀粉酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高呈现显著的下降趋势(P<0.05),但饲料中蛋白(30%,35%)和脂肪(8%,11.5%,15%)含量较高时,淀粉酶活性较稳定;肠道和肝胰脏的脂肪酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高,呈显著上升的趋势(P<0.05),但在蛋白含量(30%,35%)和脂肪含量(8%、11.5%,15%)的6个试验组之间差异不显著(P>0.05);在脂肪含量分别为4.5%、8%和11.5%时,饲料的蛋白含量对肠道的脂肪酶活性无显著性影响(P>0.05),当脂肪含量为15%时,随着蛋白含量的升高,肠道的脂肪酶活性显著降低(P<0.05)。结果表明,草鱼饲料中蛋白含量为30%和脂肪为8%(即蛋白能量比21.7 mg/kJ)的试验组草鱼获得较高的消化酶活性。  相似文献   

酶法水解牦牛血制备蛋白多肽粉的技术研究     

韩学燕  曹效海 《中国农学通报》2018,34(17):115-121

摘 要：[目的][方法]利用中性蛋白酶将牦牛血红蛋白水解,探讨各因素对中性蛋白酶水解牦牛血红蛋白的影响以及水解度的关系,并对酶解液进行了活性炭脱色效果的研究。通过单因素和正交试验（L16(45)）,[结果]确定了中性蛋白酶水解血红蛋白的适宜条件为 pH 7.0,温度 45℃,酶底物浓度比 4000 U/g 蛋白质液,底物浓度 5%,酶解时间 7 h。通过正交试验,确定酶解液的最佳脱色工艺条件为活性炭用量 4%,脱色温度 75℃,pH 5.0,脱色时间 60 min。  相似文献   

Effect of Setting Condition on the Gel-Forming Ability of Rohu     

Phatthira Sutloet  Katsuji Morioka 《Journal Of Aquatic Food Product Technology》2018,27(2):247-257

To investigate the setting condition of the gel-forming ability of rohu, optimum setting temperature for strong and weak gels of unwashed and washed rohu gel and optimum setting time for maximum proteolytic activity were investigated. Nine setting temperatures were studied for textural properties and trichloroacetic acid (TCA)-soluble peptide contents. Both unwashed gel (UW-gel) and washed gel (W-gel) showed similar optimum setting conditions for producing a strong gel that was set at 40°C for 30 min, followed by heating at 90°C for 20 min. They displayed different optimum setting conditions for weak gel. Weak gel from the degradation of UW-gel and W-gel formed at 65 and 60°C, respectively. The occurrence of protein degradation of W-gels during setting at 60°C suggested that washing did not remove the endogenous protease, and the degradation of unwashed and washed mince was due to water-soluble protease and myofibril-bound protease, respectively. Eight setting times for maximum proteolytic activity were shown by the TCA-soluble peptide contents, accompanying the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern. Both gels had similar results for setting for 120 min.  相似文献