Purification and characterization of a novel enzyme, L-threo-3-hydroxyaspartate dehydratase, from Pseudomonas sp. T62.
Purification and characterization of a novel enzyme, L-threo-3-hydroxyaspartate dehydratase, from Pseudomonas sp. T62.
复制标题
假单胞菌中一种新型酶 L-threo-3-羟基天冬氨酸脱水酶的纯化和表征。
DOI：
10.1111/j.1574-6968.1999.tb08720.x
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发表时间：
1999
影响因子：
2.1
通讯作者：
Sakayu Shimizu
中科院分区：
文献类型：
--
作者：
M. Wada;Tomoko Matsumoto;S. Nakamori;Mitsuru Sakamoto;M. Kataoka;Ji;N. Itoh;Hideaki Yamada;Sakayu Shimizu
L-苏型-3-羟基天冬氨酸脱氢酶（L-苏型-3-羟基天冬氨酸水解酶）对L-苏型-3-羟基天冬氨酸显示特异性（K（m）=0.74 mM，V（max）=37.5 μ mol min（-1）（mg蛋白）（-1）），但对D-苏型或D，L-苏型-3-羟基天冬氨酸不显示特异性，该酶从假单胞菌属T62的无细胞提取物中纯化。羟胺和EDTA对酶的活性有抑制作用，说明磷酸吡哆醛和二价阳离子参与了酶的反应。NH（2）-末端氨基酸序列显示出与酿酒酵母YKL 218 c基因产物（一种假设的苏氨酸脱氢酶）显著相似。然而，纯化的酶显示没有苏氨酸转氨酶活性。
L-threo-3-Hydroxyaspartate dehydratase (L-threo-3-hydroxyaspartate hydro-lyase), which exhibited specificity for L-threo-3-hydroxyaspartate (K(m)=0.74 mM, V(max)=37.5 micromol min(-1) (mg protein)(-1)) but not for D-threo or D, L-erythro-3-hydroxyaspartate, was purified from a cell-free extract of Pseudomonas sp. T62. The activity of the enzyme was inhibited by hydroxylamine and EDTA, which suggests that pyridoxal 5'-phosphate and divalent cations participate in the enzyme reaction. The NH(2)-terminal amino acid sequence showed significant similarity to the Saccharomyces cerevisiae YKL218c gene product, a hypothetical threonine dehydratase. However, the purified enzyme showed no threonine dehydratase activity.