高级植物中维生素C的生物合成途径
G L Wheeler1, M A Jones, N Smirnoff
1School of Biological Sciences, University of Exeter, Hatherly Laboratories, UK.
Nature
|June 10, 1998
概括
科学家们发现了植物合成维生素C (L-ascorbic acid) 的途径. 这一发现,确定了关键的前体和酶,使工程植物能够提高营养价值和耐压力.
科学领域:
- 植物生物化学 植物生物化学
- 代谢途径 代谢途径
- 营养科学 营养科学
背景情况:
- 人类不能合成维生素C (L-甲酸),依靠植物作为主要的饮食来源.
- 植物中L-甲酸的生物合成途径在很大程度上是未知的,与众所周知的动物途径不同.
- 酸在植物中丰富,可能在光合作用和电子运输中发挥作用.
研究的目的:
- 为了阐明植物中L-甲酸未知的生物合成途径.
- 确定参与植物维生素C合成的关键酶和中间体.
- 为工程工厂提供基础,增加维生素C含量.
主要方法:
- 研究了D-曼诺斯和L-银糖作为甲酸盐合成的前体.
- 识别了GDP-D-曼诺-3,5-表皮酶和L-银糖脱酶.
- 从GDP-D-mannose中合成的ascorbate在体外使用已识别的中间体.
主要成果:
- D-曼诺糖和L-银糖是高效的前体,由GDP-D-曼诺糖-3,5-epimerase相互转化.
- L-银河糖脱酶催化L-银河糖转化为L-银河糖-1,4-银河糖.
- 一个拟议的途径涉及GDP-D-曼诺斯,GDP-L-银糖,L-银糖和L-银糖-1,4-乳酸盐.
结论:
- 已经定义了L-亚斯科布酸的植物生物合成途径.
- 这一途径涉及GDP-D-曼诺糖,GDP-L-银糖,L-银糖和L-银糖-1,4-乳糖.
- 了解这种途径可以使工程植物通过增加维生素C的产量来提高其营养价值和耐压力.
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