Takechi M, Kanda M, Hori K, Kurotsu T, Saito Y
Department of Biochemistry, Hyogo College of Medicine.
J Biochem. 1994 Nov;116(5):955-9. doi: 10.1093/oxfordjournals.jbchem.a124652.
In gramicidin S-producing Bacillus brevis, the addition of L-ornithine to the minimal medium with L-glutamate as the sole carbon and nitrogen source caused an 8-fold induction of L-ornithine delta-aminotransferase [EC 2.6.1.13]. The enzyme was purified to homogeneity. The native enzyme had a molecular weight of about 88,000 after gel filtration and consisted of two subunits with an identical in molecular weight of about 45,000. The enzyme was specific for L-ornithine (Km = 1.05 mM) as an amino donor and for 2-oxoglutarate (Km = 6.25 mM) as an amino acceptor, and catalyzed the conversion of L-ornithine and 2-oxoglutarate, respectively, to glutamic-gamma-semialdehyde, which is spontaneously cyclized to delta 1-pyrroline-5-carboxylate and L-glutamate. The enzyme exhibits an absorption maximum at 425 nm at neutral pH, and 1 mol of pyridoxal phosphate is bound per subunit. The enzyme activity was irreversibly inhibited by gabaculine, and L-ornithine protected the enzyme from the inhibition. The N-terminal amino acid sequence revealed a noteworthy similarity between human and yeast L-ornithine delta-aminotransferases in residues 17-28 of the B. brevis enzyme.
在产生短杆菌肽S的短短芽孢杆菌中，在以L-谷氨酸作为唯一碳源和氮源的基本培养基中添加L-鸟氨酸，可使L-鸟氨酸δ-氨基转移酶[EC 2.6.1.13]的产量提高8倍。该酶被纯化至同质。经凝胶过滤后，天然酶的分子量约为88,000，由两个分子量相同的亚基组成，约为45,000。该酶对作为氨基供体的L-鸟氨酸（Km = 1.05 mM）和作为氨基受体的2-氧代戊二酸（Km = 6.25 mM）具有特异性，并分别催化L-鸟氨酸和2-氧代戊二酸转化为谷氨酸-γ-半醛，后者可自发环化生成δ1-吡咯啉-5-羧酸和L-谷氨酸。该酶在中性pH下于425 nm处有最大吸收峰，每个亚基结合1摩尔磷酸吡哆醛。加巴喷丁可不可逆地抑制该酶的活性，L-鸟氨酸可保护该酶免受抑制。N端氨基酸序列显示，短短芽孢杆菌酶的第17 - 28位残基与人及酵母的L-鸟氨酸δ-氨基转移酶之间存在显著相似性。
