Kataoka M, Wada M, Nishi K, Yamada H, Shimizu S
Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
FEMS Microbiol Lett. 1997 Jun 15;151(2):245-8. doi: 10.1111/j.1574-6968.1997.tb12577.x.
L-allo-Threonine aldolase (L-allo-threonine acetaldehyde-lyase), which exhibited specificity for L-allo-threonine but not for L-threonine, was purified from a cell-free extract of Aeromonas jandaei DK-39. The purified enzyme catalyzed the aldol cleavage reaction of L-allo-threonine (K(m) = 1.45 mM, Vmax = 45.2 mumol min-1 mg-1). The activity of the enzyme was inhibited by carbonyl reagents, which suggests that pyridoxal-5'-phosphate participates in the enzymatic reaction. The enzyme does not act on either L-serine or L-threonine, and thus it can be distinguished from serine hydroxy-methyltransferase (L-serine:tetrahydrofolate 5,10-hydroxy-methyltransferase, EC 2.1.2.1) or L-threonine aldolase (EC 4.1.2.5).
L-别苏氨酸醛缩酶（L-别苏氨酸乙醛裂解酶），对L-别苏氨酸具有特异性，而对L-苏氨酸无特异性，从詹氏气单胞菌DK-39的无细胞提取物中纯化得到。纯化后的酶催化L-别苏氨酸的醛醇裂解反应（米氏常数Km = 1.45 mM，最大反应速度Vmax = 45.2 μmol min⁻¹ mg⁻¹）。该酶的活性受到羰基试剂的抑制，这表明磷酸吡哆醛参与了酶促反应。该酶对L-丝氨酸或L-苏氨酸均无作用，因此可与丝氨酸羟甲基转移酶（L-丝氨酸：四氢叶酸5,10-羟甲基转移酶，EC 2.1.2.1）或L-苏氨酸醛缩酶（EC 4.1.2.5）区分开来。
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