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首页> 外文学位 >1. Selective facilitated transport of biological compounds through a phospholipid bilayer using boronic acid complexation. 2. Influence of eluent anions in boronate affinity chromatography. 3. Photoregulation of enzyme activity: Synthesis and study of pho
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1. Selective facilitated transport of biological compounds through a phospholipid bilayer using boronic acid complexation. 2. Influence of eluent anions in boronate affinity chromatography. 3. Photoregulation of enzyme activity: Synthesis and study of pho

机译：1.使用硼酸络合选择性促进生物化合物通过磷脂双层的运输。 2.洗脱液阴离子在硼酸酯亲和色谱中的影响。 3.酶活性的光调节：磷酸的合成与研究

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摘要

This dissertation encompasses three main topics: (1) the development of artificial and biological membrane transport systems for compounds which contain vicinal cis-diols, such as monosaccharides and nucleoside derivatives, (2) the development of new techniques in boronate affinity chromatography for the isolation of biological compounds at neutral pH, and (3) the development of photoswitchable enzyme inhibitors that can reversibly inhibit enzyme activity. Key to these subject matters is the use of reversible boronic acid complexation.;Boronic acids were found to facilitate the transport of monosaccharides and nucleosides in and out of liposomes. Boronic acids are the only artificial compounds that can selectively facilitate monosaccharide transport through bilayer membranes with the selectivity being sorbitol $>$ fructose $>$ glucose. Mechanistic studies indicate that the diol transport mechanism involves transient formation of a lipophilic, trigonal boronate ester. Further studies with E. coli showed that 5-fluorouridine has enhanced antibiotic activity in the presence of boronic acids.;New techniques in boronate affinity chromatography were developed for the isolation of biological compounds at neutral pH. Evidence showed that the eluent anions increased diol retention on commercially available boronate affinity columns by stabilizing the boronate-diol complexation. At pH 7.0, F$sp-$ ions enhanced ribonucleoside binding more effectively than any other anion examined. This finding has potential practical value as a simple method of increasing diol-specific binding while maintaining conditions close to physiological parameters, as well as providing insight into the mechanism of boronate-diol complexation.;The enzyme catalytic activities of chymotrypsin, subtilisin, and papain were found to be reversibly controlled with azobenzene transition-state-analogue inhibitors. Photomodulation of the shape of the inhibitor resulted in significant regulation of the inhibitory abilities. Attempts were made to immobilize a photoswitchable inhibitor to a solid support and use the matrix to extract enzymes from a solution in a reversible manner. Although initial results proved the technique to be problematic, there is still potential for its application in protein purification.
机译：本论文包括三个主要主题：（1）人工和生物膜转运系统的开发，这些系统包含邻位顺式二醇，例如单糖和核苷衍生物；（2）硼酸亲和层析中新技术的分离在中性pH值下生物化合物的合成；以及（3）可以可逆地抑制酶活性的可光转换酶抑制剂的开发。这些主题的关键是可逆硼酸络合物的使用。硼酸被发现可以促进单糖和核苷进出脂质体的转运。硼酸是唯一可以选择性地促进单糖通过双层膜运输的人造化合物，其选择性为山梨糖醇>果糖>葡萄糖。机理研究表明，二醇的运输机理涉及亲脂性三角硼酸酯的瞬时形成。对大肠杆菌的进一步研究表明，在存在硼酸的情况下，5-氟尿苷具有增强的抗生素活性。在硼酸亲和色谱中开发了新技术，用于在中性pH下分离生物化合物。有证据表明，洗脱剂阴离子通过稳定硼酸酯-二醇的络合作用，增加了二醇在市售硼酸酯亲和柱上的保留率。在pH 7.0下，F $ sp- $离子比其他任何检测到的阴离子更有效地增强了核糖核苷的结合。这一发现具有潜在的实用价值，可以作为一种简单的方法来增加二醇特异性结合，同时保持接近生理参数的条件，并提供对硼酸酯-二醇络合机理的见解。胰凝乳蛋白酶，枯草杆菌蛋白酶和木瓜蛋白酶的酶催化活性被发现是由偶氮苯过渡态类似物抑制剂可逆控制的。抑制剂形状的光调节导致抑制能力的显着调节。尝试将光可切换抑制剂固定在固体支持物上，并使用基质以可逆方式从溶液中提取酶。尽管初步结果证明该技术存在问题，但其在蛋白质纯化中的应用仍有潜力。

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  • 作者

    Westmark, Pamela Rae.;

  • 作者单位

    University of Notre Dame.;

  • 授予单位 University of Notre Dame.;
  • 学科 Biochemistry.;Chemical engineering.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 279 p.
  • 总页数 279
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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