共查询到17条相似文献，搜索用时 296 毫秒
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豆渣固体发酵产纳豆激酶的工艺优化及其部分酶学性质研究 总被引：2，自引：1，他引：1
研究纳豆菌固体发酵产纳豆激酶的工艺及其部分酶学性质.采用单因素和正交试验,对以豆渣为原料纳豆菌固体发酵生产纳豆激酶的工艺条件进行优化,并利用最佳发酵工艺制备纳豆激酶粗品,对纳豆激酶的部分性质进行研究.结果表明固体发酵培养基最佳配比:豆渣:麸皮=5:2,初始含水量65%,接种量为10%,初始pH为8.0,培养温度30℃.采用最适培养基和优化工艺,在250 m1三角瓶中进行验证实验,纳豆激酶的酶的产率可达到1577U·g-1.酶学性质研究表明,最适反应温度为60℃,37℃以下稳定,最适反应pH为8.0,在pH7-9溶液中基本稳定.体外溶栓作用表明,纳豆激酶溶解纤维蛋白的方式是直接溶解,而不是通过激活纤溶酶原. 相似文献
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纳豆是日本的传统食品,由纳豆芽孢杆菌发酵制作而成,其分泌的纳豆激酶具有安全性高、溶栓性能力强等特点。近些年来,纳豆芽孢杆菌(Bacillus natto)在食品及农副产物深加工领域应用越来越广泛,生产了多种活性产物并有效地提高了食品的营养特性。纳豆激酶除溶栓外更多最新的功能活性也逐渐被研究者发现,在稳定性及气味改良等方面的改善也有着很大的进步。本文综述了纳豆芽孢杆菌及纳豆激酶的开发及应用现状及存在的瓶颈问题和解决对策等研究进展,以期为纳豆相关食品的开发提供支持。 相似文献
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纳豆激酶高产菌株的筛选及发酵条件的优化 总被引：5，自引：0，他引：5
纳豆是日本的传统发酵食品，对人体有抗癌、延缓衰老等保健作用。从纳豆中提取出的纳豆激酶具有很强的溶解血栓的能力。本文针对我国酱豆和日本纳豆中筛选出的高活力菌株进行比较，筛选出活力最高的菌株，并确定了最优的发酵条件。 相似文献
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【目的】建立水稻叶片蛋白的多反应监测(MRM)质谱绝对定量方法。【方法】水稻叶片蛋白经含1.0%十二烷基硫酸钠(SDS)的磷酸盐(PBS)缓冲液提取,丙酮沉淀除杂纯化、胰蛋白酶消化,酶解液经液相色谱分离,MRM质谱监测,外标法定量。【结果】向提取缓冲液中加入1.0%SDS可增强水稻叶片中16种靶蛋白和总蛋白质的提取效果;不同有机试剂处理,总蛋白质沉淀量存在显著差异(P<0.05),沉淀能力从强到弱依次为乙腈>丙酮>异丙醇>甲醇>乙醇;对于16种目标蛋白,总体以丙酮沉淀效果最好,其次是异丙醇和乙腈,甲醇和乙醇效果较差。该方法线性范围均达到3个数量级,定量限为0.1~2.5 nmol/L,灌浆期16种水稻叶片蛋白质含量为6.0~2818.1μg/g,相对标准偏差均小于14%。【结论】SDS可显著提高水稻叶片蛋白提取效果,采用丙酮或乙腈可获得较好的蛋白沉淀效果,但不同蛋白质略有差异。结合MRM质谱监测技术可实现水稻叶片蛋白的绝对定量,方法线性范围宽、敏度高、重复性好。 相似文献
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【Objective】An absolute quantitative method for proteins in rice leaf based on multiple reaction monitoring (MRM) mass spectrometry was established.【Method】The proteins in rice leaf were extracted with PBS buffer containing 1.0% sodium dodecyl sulfate(SDS), purified by acetone precipitation, and then digested by Trypsin. The enzymatic hydrolysate was separated by liquid chromatography, monitored by MRM mass spectrometry and quantified by external standard method.【Results】The addition of 1.0% SDS to the extraction buffer enhanced the extraction effect of 16 kinds of target proteins and total proteins in rice leaf. Total proteins precipitation with several solvents varied significantly (P<0.05), and the precipitation ability from strong to weak was acetonitrile>acetone>isopropanol>methanol>ethanol. Acetone performed best in the precipitation effect of 16 kinds of target proteins, followed by isopropanol and acetonitrile, and methanol and ethanol represented the worst precipitants. The relative standard deviations of the method were all less than 14% in three orders of magnitude range, with the quantification limit from 0.1 to 2.5 nmol/L, and the contents of 16 kinds of proteins in rice leaf during the grain filling stage ranged from 6.0 to 2818.1 μg/g.【Conclusion】SDS could significantly improve the extraction effect of proteins in rice leaf. Acetone and acetonitrile addition generated excellent precipitation effects of proteins, with slight difference in various proteins. Combined with MRM mass spectrometry technology, the absolute quantification method for proteins in rice leaf is featured by wide-linear range, high sensitivity and good repeatability. 相似文献
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【目的】研究dynamin-1-like的两个基因NlDNM1L-1和NlDNM1L-2在褐飞虱中的生物学功能。【方法】通过聚合酶链式反应扩增褐飞虱dynamin-1-like的两个基因,并对其生物信息学进行分析。通过荧光定量PCR技术(qPCR)检测了这两个基因在褐飞虱不同组织和不同发育阶段中的相对表达量。构建原核表达载体,在表达菌株Rosetta中诱导重组目的蛋白的表达。通过Ni柱亲和层析纯化目的蛋白,并将纯化得到的蛋白免疫新西兰大白兔,得到多克隆抗体,并用ELISA检测抗体效价,Western blotting检测抗体特异性。利用上述抗体,通过免疫荧光实验观察目的蛋白在褐飞虱卵巢中的表达和定位。【结果】克隆并鉴定了两个dynamin-1-like基因,分别命名为NlDNM1L-1和NlDNM1L-2(Gen Bank登录号分别为KY082900、KY082901)。系统进化树表明,NlDNM1L-1和NlD NM1L-2在半翅目昆虫中较为保守。蛋白结构预测和基因时空表达分析说明,NlDNM1L-1和NlDNM1L-2在褐飞虱中可能有着不同的功能。ELISA和Western blotting结果表明,制备的NlDNM1L-1和NlDNM1L-2多克隆抗体效价高、特异性好。免疫荧光实验结果显示,NlDNM1L-1和NlDNM1L-2在褐飞虱卵巢滤泡细胞中普遍表达,可能与褐飞虱卵巢发育和成熟有关,它们也可能与类酵母共生菌入侵褐飞虱卵巢有关。【结论】获得了NlDNM1L-1和NlDNM1L-2基因序列,了解了其基本的生物信息,并阐明了其时空表达特征;成功制备其多克隆抗体,并初步了解了NlDNM1L-1和NlDNM1L-2在褐飞虱卵巢中的表达和定位。这些结果为深入研究NlDNM1L-1和NlDNM1L-2在褐飞虱中的功能奠定了基础。 相似文献
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采用RACE技术扩增2株Bacillus属菌株XY18、XY20的β-D-葡萄糖苷酶编码基因bgl全长,构建重组载体pET28a(+)/bgl、pET28b(+)/bgl,导入E. coli BL21诱导表达,采用Ni亲和层析纯化蛋白。经酶学性质测定发现：2个蛋白均为弱酸性蛋白,温度为40 ℃时酶活力达到最大,具有一定耐热性。以上结果表明,为优化2株Bacillus属菌株参与香草兰发酵工艺,可提供适当弱酸性条件、适宜温度。 相似文献
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富甘氨酸蛋白(glycine rich proteins,GRPs)在植物逆境响应中发挥重要作用。前期通过全基因组关联分析获得油菜响应低磷胁迫的候选基因BnGRP1，但是其响应低磷胁迫的分子机制尚不明确。序列分析发现，BnGRP1的CDS全长为399 bp，编码132个氨基酸，其中62个为甘氨酸，占该蛋白氨基酸总量的47.0%。为进一步研究BnGRP1的生物学功能，本研究通过CRISPR/Cas9技术构建了目标基因的双靶点载体G2-TD1TD2，并遗传转化甘蓝型油菜，通过筛选鉴定获得了13株T0代转基因阳性植株。通过TA克隆和测序技术分析了5株转基因植株中Bngrp1的突变位点，其中3株的目标基因序列发生突变，导致无法编码形成正常的富甘氨酸蛋白。本研究为研究BnGRP1的生物学功能提供了实验材料，也为进一步研究BnGRP1响应低磷胁迫的分子机制提供理论和实验基础。 相似文献
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K. Gebruers K. Brijs C. M. Courtin H. Goesaert P. Proost J. Van Damme J. A. Delcour 《Journal of Cereal Science》2002,36(3):367
An affinity-based purification procedure allowed the resolution of two distinct groups of endoxylanase inhibitors with different molecular structures and endoxylanase specificities from wheat wholemeal. The first group comprises the so-called Triticum aestivum L. Endoxylanase inhibitor (TAXI)-type proteins which are of approx. Mr 40 000 and occur in two different molecular forms. These inhibitors were removed from a concentrated cation exchange chromatography fraction from wheat wholemeal on a Bacillus subtilis endoxylanase affinity column. The second group of structurally different endoxylanase inhibitors, the so-called xylanase inhibiting protein (XIP)-type, of approx.Mr 29 000–32 000, with pI values varying between 8·8 and 9·2, was purified from the unbound fraction from the B. subtilis endoxylanase affinity column by chromatography on an Aspergillus niger endoxylanase affinity column followed by gel permeation chromatography. The XIP-type inhibitors are not active against the B. subtilis endoxylanase and were consequently not retained on the B. subtilis endoxylanase column. Further analysis of the XIP-type proteins by high-resolution cation exchange chromatography, SDS-PAGE and iso-electrofocusing, revealed several forms. They had similar endoxylanase specificities and N-terminal amino acid sequences. 相似文献