Saito K
The Radioisotope Research Center, Kyoto University, Kyoto 606, Japan.
Plant Physiol. 1978 Aug;62(2):215-9. doi: 10.1104/pp.62.2.215.
[U-(14)C]Sucrose, myo-[U-(14)C]inositol, [6-(14)C]- and [U-(14)C]glucuronate, UDP-[U-(14)C]glucuronate, [U-(14)C]gluconate, and l-[1-(14)C]ascorbic acid were fed into grape berries, Vitis labrusca L. cv. Delaware, at intervals throughout the ripening process and incorporation of (14)C into several metabolites was studied.[U-(14)C]Sucrose was the most effective precursor of cellulose in young grape berries and of glucose and fructose in mature berries. On the other hand, UDP-[U-(14)C]glucuronate was the best precursor of pectic substance, followed by [(14)C]glucuronate and myo-[U-(14)C]inositol. l-[1-(14)C]Ascorbic acid was the most effective precursor of tartaric acid. In young berries, [U-(14)C]sucrose and [U-(14)C]gluconate also produced labeled tartaric acid, the latter a somewhat better precursor in the 3 weeks following flowering. The remaining test compounds were only poor sources of (14)C for tartaric acid although all three, glucuronate, UDP-glucuronate, and myo-inositol, were utilized by the grape berry for pectin biosynthesis.These results strongly indicate that tartaric acid is synthesized by a C-1 oxidation mechanism of hexose in young grape berries.
在整个成熟过程中，每隔一段时间将[U-(14)C]蔗糖、肌醇-[U-(14)C]肌醇、[6-(14)C]-和[U-(14)C]葡萄糖醛酸、UDP-[U-(14)C]葡萄糖醛酸、[U-(14)C]葡萄糖酸和L-[1-(14)C]抗坏血酸喂入葡萄浆果（美洲葡萄L.品种特拉华）中，并研究(14)C掺入几种代谢物的情况。[U-(14)C]蔗糖是幼嫩葡萄浆果中纤维素以及成熟浆果中葡萄糖和果糖的最有效前体。另一方面，UDP-[U-(14)C]葡萄糖醛酸是果胶物质的最佳前体，其次是[(14)C]葡萄糖醛酸和肌醇-[U-(14)C]肌醇。L-[1-(14)C]抗坏血酸是酒石酸的最有效前体。在幼嫩浆果中, [U-(14)C]蔗糖和[U-(14)C]葡萄糖酸也产生标记的酒石酸，后者在开花后的3周内是稍好的前体。其余测试化合物只是酒石酸的(14)C的不良来源，尽管葡萄糖醛酸、UDP-葡萄糖醛酸和肌醇这三者都被葡萄浆果用于果胶生物合成。这些结果有力地表明，幼嫩葡萄浆果中的酒石酸是通过己糖的C-1氧化机制合成的。
