从玉米胚乳和根中获得的谷氨酸合酶的比较。
A comparison of glutamate synthase obtained from maize endosperms and roots.
作者信息
Oaks A, Jones K, Misra S
机构信息
Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1 Canada.
出版信息
Plant Physiol. 1979 May;63(5):793-5. doi: 10.1104/pp.63.5.793.
Glutamate synthase (EC 2.6.1.53) has been examined in developing endosperms and roots of maize. KCl is required for maximum activity in each tissue. The effect with KCl is seen with buffer strength of 25 to 100 millimolar in the assay. The optimum concentration for the enzyme from endosperm is 20 millimolar and for the enzyme from root tissue the saturating concentration is about 20 millimolar. In root material the enzyme is labile but activity can be restored if KCl is added to the assay. Divalent cations such as Mg(2+) or Mn(2+) also activate the enzyme to some extent.In each case NADH or NADPH can serve as reductant. The reaction is insensitive to alpha-aminooxyacetate, but is inhibited by glutamate, the glutamate analogs methionine sulfoximine and methionine sulfone, and by the glutamine analogs azaserine and albizziin.
已对玉米发育中的胚乳和根中的谷氨酸合酶（EC 2.6.1.53）进行了研究。在每个组织中，最大活性都需要氯化钾。在测定中，当缓冲液强度为25至100毫摩尔时可观察到氯化钾的作用。胚乳中该酶的最佳浓度为20毫摩尔，根组织中该酶的饱和浓度约为20毫摩尔。在根材料中，该酶不稳定，但如果在测定中添加氯化钾，活性可以恢复。二价阳离子如Mg(2+)或Mn(2+)也能在一定程度上激活该酶。在每种情况下，NADH或NADPH都可以作为还原剂。该反应对α-氨基氧乙酸不敏感，但受到谷氨酸、谷氨酸类似物甲硫氨酸亚砜亚胺和甲硫氨酸砜以及谷氨酰胺类似物重氮丝氨酸和合欢氨酸的抑制。
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