Mueckler M M, Pitot H C
J Biol Chem. 1985 Oct 25;260(24):12993-7.
The nucleotide sequence of ornithine aminotransferase mRNA from rat liver, including the entire coding and 3' untranslated regions, was determined from two overlapping cDNA clones. The mRNA encodes a precursor polypeptide of 439 amino acid residues with a molecular weight of 48,332. The deduced amino acid composition of the proposed mature enzyme sequence (residues 35 through 439) was in good agreement with that reported for the purified protein. The amino-terminal segment of the precursor corresponding to residues 1 through 34 has an overall positive charge, containing 6 basic residues and only a single acidic residue, and is postulated to be the mitochondrial leader sequence. The first 22 amino acid residues of the proposed leader sequences share 54% homology with the leader peptide of rat ornithine transcarbamylase precursor and more limited homology to the leader peptides of other nuclear-encoded mitochondrial matrix proteins. Homology was also observed between residues 286 through 362 ornithine aminotransferase precursor and a region containing the pyridoxyl phosphate binding domain of mitochondrial aspartate aminotransferase.
从两个重叠的 cDNA 克隆中确定了大鼠肝脏鸟氨酸氨基转移酶 mRNA 的核苷酸序列，包括整个编码区和 3' 非翻译区。该 mRNA 编码一个由 439 个氨基酸残基组成的前体多肽，分子量为 48,332。推导的成熟酶序列（第 35 至 439 位残基）的氨基酸组成与纯化蛋白报道的结果高度一致。前体的氨基末端片段对应于第 1 至 34 位残基，整体带正电荷，含有 6 个碱性残基且只有一个酸性残基，推测为线粒体前导序列。推测的前导序列的前 22 个氨基酸残基与大鼠鸟氨酸转氨甲酰酶前体的前导肽有 54% 的同源性，与其他核编码线粒体基质蛋白的前导肽同源性较低。在鸟氨酸氨基转移酶前体的第 286 至 362 位残基与线粒体天冬氨酸氨基转移酶含磷酸吡哆醛结合域的区域之间也观察到同源性。
