Mazelis M, Pratt H M
Department of Biochemistry, Rothamsted Experimental Station, Harpenden, Herts AL5 2JQ, England.
Plant Physiol. 1976 Jan;57(1):85-7. doi: 10.1104/pp.57.1.85.
l-(U-(14)C)-5-oxoproline (pyrollidone carboxylic acid or pyroglutamic acid) was infiltrated into detached leaves of a number of species and incubated for 1 to 6 hours. In every case, conversion to labeled glutamate and glutamine was observed. The amount converted varied from 1 to 64% of the total label fed depending on the species. The ratio of glutamate-(14)C to glutamine-(14)C ranged from 5 in Vicia faba to 1 in sugar beet. This ratio could be affected by preinfiltrating various compounds before allowing the uptake of the 5-oxoproline. When l-methionine-dl-sulfoximine was prefed to sugar beet leaves, the glutamate-glutamine ratio increased from 1 to 10. Prior treatment of V. faba leaves with azaserine resulted in essentially only labeled glutamine being recovered. Preinfiltration with NaF or ATP gave similar results in that the glutamate-glutamine ratio was greatly decreased. The results are consistent with glutamate being produced from the 5-oxoproline and then being converted to glutamine.
L-(U-(14)C)-5-氧代脯氨酸（吡咯烷酮羧酸或焦谷氨酸）被渗入多种植物的离体叶片中，并孵育1至6小时。在每种情况下，均观察到其转化为标记的谷氨酸和谷氨酰胺。根据植物种类的不同，转化量占所提供总标记量的1%至64%不等。谷氨酸-(14)C与谷氨酰胺-(14)C的比例在蚕豆中为5，在甜菜中为1。在允许5-氧代脯氨酸吸收之前，预先渗入各种化合物可能会影响该比例。当向甜菜叶片预先饲喂L-蛋氨酸-dl-亚砜亚胺时，谷氨酸-谷氨酰胺比例从1增加到10。用重氮丝氨酸预先处理蚕豆叶片后，基本上只回收了标记的谷氨酰胺。用氟化钠或ATP预先渗入也得到了类似的结果，即谷氨酸-谷氨酰胺比例大大降低。这些结果与5-氧代脯氨酸产生谷氨酸然后再转化为谷氨酰胺的过程是一致的。
