Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
Biochemistry. 2010 Feb 16;49(6):1226-35. doi: 10.1021/bi901812p.
The gene identification and kinetic characterization of (E)-2-(acetamidomethylene)succinate (E-2AMS) hydrolase has recently been described. This enzyme catalyzes the final reaction in the degradation of vitamin B(6) and produces succinic semialdehyde, acetate, ammonia, and carbon dioxide from E-2AMS. The structure of E-2AMS hydrolase was determined to 2.3 A using SAD phasing. E-2AMS hydrolase is a member of the alpha/beta hydrolase superfamily and utilizes a serine/histidine/aspartic acid catalytic triad. Mutation of either the nucleophilic serine or the aspartate resulted in inactive enzyme. Mutation of an additional serine residue in the active site causes the enzyme to be unstable and is likely structurally important. The structure also provides insight into the mechanism of hydrolysis of E-2AMS and identifies several potential catalytically important residues.
(E)-2-(乙酰亚氨甲基)琥珀酸 (E-2AMS) 水解酶的基因鉴定和动力学特性最近已被描述。这种酶催化维生素 B(6) 降解的最后一步反应，从 E-2AMS 产生琥珀酸半醛、醋酸盐、氨和二氧化碳。使用 SAD 相位测定法确定 E-2AMS 水解酶的结构为 2.3 A。E-2AMS 水解酶是α/β水解酶超家族的成员，利用丝氨酸/组氨酸/天冬氨酸催化三联体。亲核丝氨酸或天冬氨酸的突变导致酶失活。活性位点中另外一个丝氨酸残基的突变使酶不稳定，这可能在结构上很重要。该结构还提供了对 E-2AMS 水解机制的深入了解，并确定了几个潜在的催化重要残基。
