Kanematsu S, Asada K
Research Institute for Food Secience, Kyoto University, Japan.
Free Radic Res Commun. 1991;12-13 Pt 1:383-90. doi: 10.3109/10715769109145808.
Isozymes of CuZn-superoxide dismutase (SOD) were purified from angiosperms (spinach and rice), fern (horsetail) and green alga (Spirogyra). Occurrence of CuZn-SOD was confirmed by its purification in the group of green algae which shows the phragmoplast type of cell division. Purified CuZn-SODs are divided to chloroplast and cytosol types by their cellular localization and immunological properties. Their amino acid compositions, absorption spectra, CD spectra, and sensitivity to hydrogen peroxide also are distinguished from each other. All organisms including Spirogyra contain both types of isozyme. Thus, the divergence of the two types of CuZn-SOD isozyme occurred immediately after its acquisition by the most evolved green algae. Amino acid sequences of amino-terminal regions of CuZn-SOD isozymes from spinach, rice and horsetail were determined and compared with those of CuZn-SODs from other plants. The chloroplast and cytosol isozymes of CuZn-SOD show each characteristic sequences. Sequence differences among the cytosol CuZn-SODs are greater than those among the chloroplast CuZn-SODs. These observations indicate that each type of isozyme had independently evolved after the acquisition of CuZn-SOD.
从被子植物（菠菜和水稻）、蕨类植物（木贼）和绿藻（水绵）中纯化了铜锌超氧化物歧化酶（SOD）的同工酶。在显示成膜体类型细胞分裂的绿藻群体中，通过其纯化证实了铜锌SOD的存在。纯化的铜锌SOD根据其细胞定位和免疫学特性分为叶绿体型和胞质溶胶型。它们的氨基酸组成、吸收光谱、圆二色光谱以及对过氧化氢的敏感性也彼此不同。包括水绵在内的所有生物都含有这两种同工酶类型。因此，两种类型的铜锌SOD同工酶在最进化的绿藻获得它之后立即发生了分化。测定了菠菜、水稻和木贼的铜锌SOD同工酶氨基末端区域的氨基酸序列，并与其他植物的铜锌SOD序列进行了比较。铜锌SOD的叶绿体和胞质溶胶同工酶显示出各自的特征序列。胞质溶胶铜锌SOD之间的序列差异大于叶绿体铜锌SOD之间的差异。这些观察结果表明，每种同工酶类型在获得铜锌SOD后独立进化。
