SYNTHESIS AND BIOCHEMISTRY OF ASCORBIC ACID ANALOGUES

抗坏血酸(维生素C)是人类健康的饮食要求， 几种酶作用的电子供体，起着 抗氧化剂，与宿主防御机制、内分泌有关 功能和视觉过程(晶状体)。最近重新燃起了对 抗坏血酸的生物化学是由认识到 关于这些物质的浓度，我们知之甚少 这几个角色的最佳功能所需的维生素。在……里面 在酶促反应的情况下，定义了过程的最优速率 因为允许反应达到Vmax的浓度在没有 毒性。作为确定这些浓度的计划的一部分，在 对某些维生素C进行了原位动力学测量。 连锁反应。除了研究功能角色之外， 维生素C，高效转运机制的最新表征 维生素C跨细胞膜的转移强调了 维生素对生物过程的重要性。动能 这些传输机制的参数也在确定中。 6-脱氧-6-卤代抗坏血酸转运抑制的动力学测定 酸性类似物清楚地证明了分离的存在 抗坏血酸和脱氢抗坏血酸的转运途径 酸。使用我们的路线得到6-芳氧基-抗坏血酸类似物，我们有 制备的放射性标记官能化类似物具有潜在的 不可逆地与抗坏血酸转运蛋白结合。这 包括6-(4-苯甲酰基苯氧基)-6-脱氧抗坏血酸，一个潜在的 亲光性标签。这种类似物是由抗坏血酸 酸性载体。 探讨2-羟基对抗坏血酸的重要性 酸活性，我们制备了2-脱氧-抗坏血酸。这个类比 正被用作制备 2-脱氧-2-卤代抗坏血酸，包括2-脱氧-2-卤代抗坏血酸。 脱氧-2-氟抗坏血酸，一种等立体和等极，非- 可氧化的，类似的。

Ascorbic acid (vitamin C), a dietary requirement for human health, is an electron donor for several enzymatic actions, functions as an antioxidant, and is implicated in host defense mechanisms, endocrine function and the visual process (lens). Recent renewed interest in the biochemistry of ascorbic acid has been prompted by the realization that relatively little is known concerning the concentrations of the vitamin required for optimum functioning of these several roles. In the case of enzymatic reactions, optimal rate of a process is defined as that concentration that allows the reaction to reach Vmax without toxicity. As part of a program to determine these concentrations, in situ kinetic measurements have been carried out for certain vitamin C- linked reactions. In addition to examination of functional roles of vitamin C, recent characterization of efficient transport mechanisms that translocate vitamin C across cellular membranes has emphasized the importance of the vitamin to biological processes. Kinetic parameters of these transport mechanisms are also being determined. Kinetic measurements of transport inhibition of 6-deoxy-6-haloascorbic acid analogues have clearly demonstrated the presence of separate pathways for the translocation of ascorbic acid and dehydroascorbic acid. Using our route to 6-aryloxy-ascorbic acid analogues, we have prepared radiolabeled functionalized analogues having the potential for irreversible binding to the ascorbic acid transporter. This incluces 6-(4-benzoylphenoxy)-6-deoxyascorbic acid, a potential photoaffinity label. This analogue is transported by the ascorbic acid carrier. To investigate the importance of the 2-hydroxyl group on ascorbic acid activity, we have prepared 2-deoxy-ascorbic acid. This analogue is being used as a starting material for the preparation of the previously unreported 2-deoxy-2-halo ascorbic acids, including 2- deoxy-2-fluoro-ascorbic acid, an isosteric and isopolar, non- oxidizable, analogue.