Kagawa M, Murakoshi N, Nishikawa Y, Matsumoto G, Kurata Y, Mizobata T, Kawata Y, Nagai J
Faculty of Engineering, Tottori University, Koyama-Minami, Tottori, 680-8552, Japan.
Arch Biochem Biophys. 1999 Feb 15;362(2):346-55. doi: 10.1006/abbi.1998.1041.
We have purified a heat-stable catalase from a thermophilic bacterium, Thermus species strain YS 8-13. The enzyme was purified 160-fold from crude cellular extracts and possessed a specific activity of 8000 units/mg at 65 degrees C. The purified enzyme displayed the highest activity at pH 7 to 10 and temperatures around 85 degrees C. The catalase was determined to be a manganese catalase, based on results from atomic absorption spectra and inhibition experiments using sodium azide. The enzyme was composed of six identical subunits of molecular weight 36,000. Amino acid sequences determined from the purified protein were used to design oligonucleotide primers, which were in turn used to clone the coding gene. The nucleotide sequence of a 1.4-kb fragment of Thermus sp. YS 8-13 genomic DNA containing a 909-bp open reading frame was determined. The gene encoded a 302-residue polypeptide of deduced molecular weight 33,303. The deduced amino acid sequence displayed a region-specific homology with the sequences of the manganese catalase from a mesophilic organism, Lactobacillus plantarum.
我们从嗜热细菌嗜热栖热菌YS 8 - 13中纯化出了一种热稳定过氧化氢酶。该酶从粗细胞提取物中纯化了160倍，在65℃时具有8000单位/毫克的比活性。纯化后的酶在pH 7至10以及约85℃的温度下表现出最高活性。基于原子吸收光谱结果和使用叠氮化钠的抑制实验，确定该过氧化氢酶为锰过氧化氢酶。该酶由六个分子量为36,000的相同亚基组成。从纯化蛋白中确定的氨基酸序列用于设计寡核苷酸引物，这些引物又用于克隆编码基因。测定了嗜热栖热菌YS 8 - 13基因组DNA中一个1.4 kb片段的核苷酸序列，该片段包含一个909 bp的开放阅读框。该基因编码一个推导分子量为33,303的302个残基的多肽。推导的氨基酸序列与嗜温生物植物乳杆菌的锰过氧化氢酶序列显示出区域特异性同源性。
