Okada H, Ueda M, Sugaya T, Atomi H, Mozaffar S, Hishida T, Teranishi Y, Okazaki K, Takechi T, Kamiryo T
Department of Industrial Chemistry, Faculty of Engineering, Kyoto University, Japan.
Eur J Biochem. 1987 Dec 30;170(1-2):105-10. doi: 10.1111/j.1432-1033.1987.tb13673.x.
A clone harbouring the genomic DNA sequence for the peroxisomal catalase of an n-alkane-utilizable yeast, Candida tropicalis, has been isolated by the hybrid-selection method and confirmed with a probe of catalase partial cDNA. Nucleotide sequence analysis of the cloned DNA disclosed that the gene fragment coding for catalase had a length of 1455 base pairs (corresponding to 485 amino acids; m = 54937 Da), and that the size of this enzyme was the smallest among all catalases reported hitherto. No intervening sequence was found in this coding region and some portions coincided with the amino acid sequences obtained from the analysis of the purified catalase. The comparison with three peroxisomal catalases from rat liver, bovine liver and human kidney, and one cytosolic catalase from Saccharomyces cerevisiae has revealed that catalase from C. tropicalis was more homologous to the peroxisomal enzymes than to the cytosolic one. C. tropicalis used the codons of the high-expression type. Amino acid residues were all conserved at the active and heme-binding sites. In the N and C-terminal regions there was no characteristic signal sequence or consensus sequence. However, a noticeable region, which can be discriminated between peroxisomal and cytosolic catalases, was proposed.
利用杂交筛选法分离得到了一个克隆，该克隆含有可利用正构烷烃的热带假丝酵母过氧化物酶体过氧化氢酶的基因组DNA序列，并用过氧化氢酶部分cDNA探针进行了验证。对克隆DNA的核苷酸序列分析表明，编码过氧化氢酶的基因片段长度为1455个碱基对（对应485个氨基酸；分子量为54937道尔顿），并且该酶的大小是迄今报道的所有过氧化氢酶中最小的。在该编码区未发现内含子序列，并且部分序列与从纯化的过氧化氢酶分析中获得的氨基酸序列一致。与来自大鼠肝脏、牛肝脏和人肾脏的三种过氧化物酶体过氧化氢酶以及来自酿酒酵母的一种胞质过氧化氢酶进行比较后发现，热带假丝酵母的过氧化氢酶与过氧化物酶体酶的同源性高于与胞质酶的同源性。热带假丝酵母使用高表达型密码子。活性位点和血红素结合位点的氨基酸残基均保守。在N端和C端区域没有特征性信号序列或共有序列。然而，提出了一个可区分过氧化物酶体过氧化氢酶和胞质过氧化氢酶的显著区域。
