Radiation chemistry of carbohydrates. Part 14. Hydroxyl radical induced oxidation of D-glucose in oxygenated aqueous solution
Radiation chemistry of carbohydrates. Part 14. Hydroxyl radical induced oxidation of D-glucose in oxygenated aqueous solution
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碳水化合物的辐射化学。
DOI：
10.1039/p29770001958
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
C. Sonntag
中科院分区：
文献类型：
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作者：
M. N. Schuchmann;C. Sonntag
D-葡萄糖(5×10~(-3)M)在N2O-O_2(80：20v/v)饱和水溶液(剂量率为1.1×10~(15)eV·g~(-1)·S~(-1))中进行γ辐照，测定了22种产物的G值。主要产物(括号内的G值)为：D-葡萄糖酸(1)(0.9)。D-阿拉伯-六糖(2)(0.9)。D-核糖基-3-果糖(3)(0.57)、D-木基-6-4-果糖(4)(0.50)、D-木基-6-5-果糖(5)(0.60)。D-葡萄糖-己二糖(6)(1.55)和L-苏氨酸(12)(0.20)。产物(1)-(6)被认为是由C-1-C-6上的OH攻击，然后是氧加成和HO2消除而形成的。在竞争中，葡萄糖过氧化自由基与HO2·(O2-·)反应导致C-C键断裂。这些裂解反应的主要产物为(12)(前体)。C-5的激进分子)。使用Van de Graaff发生器的电子脉冲进行的剂量率研究表明，HO2·的消除速率顺序为：C-1、C-2、C-3、C-4和GT；C-6、C-5。此外，还计算了OH自由基从C-1和C-2中抽出氢原子的几率约为20%。C-3和C-4约为10%，C-5约为15%，C-6约为30%。
D-Glucose (5 × 10–3M) has been γ-irradiated in N2O–O2(80 : 20 v/v) saturated aqueous solutions (dose rate 1.1 × 1015 eV g–1 s–1), and the G values of 22 products determined. Major products (G values in parentheses) are : D-gluconic acid (1)(0.9). D-arabino-hexosulose (2)(0.9). D-ribo-hexos-3-ulose (3)(0.57), D-xylo-hexos-4-ulose (4)(0.50), D-xylo-hexos-5-ulose (5)(0.60). D-gluco-hexodialdose (6)(1.55), and L-threo-tetrodialdose (12)(0.20). Products (1)–(6) are thought to be formed by OH attack at C-1–C-6, followed by oxygen addition and and HO2 elimination. In competition, reactions between the glucose peroxyl radicals and HO2·(O2–·) give rise to fragmentation of C–C bonds. The major product from these fragmentation reactions is (12)(precursor. radical at C-5). From a dose rate study using electron pulses from a van de Graaff generator it has been shown that the rates of HO2· elimination are in the order: C-1 C-2, C-3, C-4 > C-6 C-5. Furthermore, it has been calculated that OH radicals abstract a hydrogen atom from C-1 and C-2 with a probability of ca. 20%. from C-3 and C-4 of ca. 10% from C-5 of ca. 15%, and from C-6 ca. 30%.