Huang T S, Law J H, Söderhäll K
Department of Physiological Botany, University of Uppsala, Sweden.
Eur J Biochem. 1996 Mar 1;236(2):450-6. doi: 10.1111/j.1432-1033.1996.00450.x.
Ferritin was purified from the hepatopancreas of the freshwater crayfish Pacifastacus leniusculus after injection of iron. It has the same size as horse spleen ferritin (440 kDa) and migrates as two bands, 19 kDa and 20 kDa, respectively, in SDS/PAGE under reducing conditions. Crayfish ferritin (20 kDa) was cloned from a hepatopancreas cDNA library. The deduced amino acid sequence of the crayfish ferritin shows a closer relationship to vertebrate ferritin heavy chains than to insect ferritin and contains the conserved H-specific residues for the ferroxidase centre found in vertebrate ferritin heavy chain. An IRE(iron-responsive element)-like sequence with a predicted stem-loop structure was present in the 5' untranslated region of the crayfish ferritin mRNA. Crayfish ferritin does not share the atypical properties of insect ferritins, such as high molecular mass of intact protein, abundance in hemolymph, and export into vacuoles. We suggest that there are two different types of ferritins distributed in different species: insect-type or secretory ferritins which are predominant in the snail oocyte and insects, and vertebrate (crustacean)-type or cytosolic ferritins which are predominant in vertebrates and crustacea.
注射铁后，从淡水小龙虾美洲鳌虾的肝胰腺中纯化出铁蛋白。它与马脾铁蛋白大小相同（440 kDa），在还原条件下的SDS/PAGE中分别以19 kDa和20 kDa两条带迁移。从小龙虾肝胰腺cDNA文库中克隆出小龙虾铁蛋白（20 kDa）。推导的小龙虾铁蛋白氨基酸序列显示，它与脊椎动物铁蛋白重链的关系比与昆虫铁蛋白的关系更密切，并且包含在脊椎动物铁蛋白重链中发现的铁氧化酶中心保守的H特异性残基。在小龙虾铁蛋白mRNA的5'非翻译区存在一个具有预测茎环结构的IRE（铁反应元件）样序列。小龙虾铁蛋白不具有昆虫铁蛋白的非典型特性，如完整蛋白质的高分子量、血淋巴中的丰富含量以及向液泡中的输出。我们认为，在不同物种中分布着两种不同类型的铁蛋白：在蜗牛卵母细胞和昆虫中占主导的昆虫型或分泌型铁蛋白，以及在脊椎动物和甲壳类动物中占主导的脊椎动物（甲壳类）型或胞质铁蛋白。
