花椰菜（甘蓝型油菜 var. botrytis L.）丝氨酸转羟甲基酶：部分纯化与性质。
Serine Transhydroxymethylase of Cauliflower (Brassica oleracea var. botrytis L.): Partial Purification and Properties.
机构信息
Department of Food Science and Technology, University of California, Davis, California 95616.
出版信息
Plant Physiol. 1967 Dec;42(12):1763-8. doi: 10.1104/pp.42.12.1763.
Serine transhydroxymethylase (EC 2.1.2.1) has been purified 46-fold from cauliflower (Brassica oleracea var. botrytis L.). The enzyme was completely dependent on the presence of tetrahydrofolic acid for the conversion of serine to glycine. The addition of pyridoxal phosphate gave a large increase in the reaction rate. A double pH optimum was observed with maxima at 7.5 and 9.5. The enzyme is specific for l-serine. The d-isomer is neither a substrate nor an inhibitor. The Michaelis constants for l-serine, tetrahydrofolic acid, and pyridoxal phosphate were 300 mum, 760 mum, and 24 mum, respectively. The addition of K(+) also stimulated the reaction rate considerably. The effect was quite specific since all other metal ions tested either had very little: influence or were extremely inhibitory.
丝氨酸羟甲基转移酶（EC 2.1.2.1）已从花椰菜（ Brassica oleracea var. botrytis L.）中纯化为 46 倍。该酶完全依赖四氢叶酸的存在将丝氨酸转化为甘氨酸。添加磷酸吡哆醛可大大提高反应速率。观察到双 pH 最佳值，最大值分别为 7.5 和 9.5。该酶对 l-丝氨酸具有特异性。d-异构体既不是底物也不是抑制剂。l-丝氨酸、四氢叶酸和磷酸吡哆醛的米氏常数分别为 300 mum、760 mum 和 24 mum。添加 K(+) 也可大大刺激反应速率。该效果非常特异，因为测试的所有其他金属离子要么影响很小，要么具有极强的抑制作用。
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