Chun J T, Gioio A E, Crispino M, Giuditta A, Kaplan B B
Department of Psychiatry, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
Neurochem Res. 1995 Aug;20(8):923-30. doi: 10.1007/BF00970738.
Enolase is a glycolytic enzyme whose amino acid sequence is highly conserved across a wide range of animal species. In mammals, enolase is known to be a dimeric protein composed of distinct but closely related subunits: alpha (non-neuronal), beta (muscle-specific), and gamma (neuron-specific). However, little information is available on the primary sequence of enolase in invertebrates. Here we report the isolation of two overlapping cDNA clones and the putative primary structure of the enzyme from the squid (Loligo pealii) nervous system. The composite sequence of those cDNA clones is 1575 bp and contains the entire coding region (1302 bp), as well as 66 and 207 bp of 5' and 3' untranslated sequence, respectively. Cross-species comparison of enolase primary structure reveals that squid enolase shares over 70% sequence identity to vertebrate forms of the enzyme. The greatest degree of sequence similarity was manifest to the alpha isoform of the human homologue. Results of Northern analysis revealed a single 1.6 kb mRNA species, the relative abundance of which differs approximately 10-fold between various tissues. Interestingly, evidence derived from in situ hybridization and polymerase chain reaction experiments indicate that the mRNA encoding enolase is present in the squid giant axon.
烯醇化酶是一种糖酵解酶，其氨基酸序列在广泛的动物物种中高度保守。在哺乳动物中，烯醇化酶是一种由不同但密切相关的亚基组成的二聚体蛋白：α（非神经元型）、β（肌肉特异性）和γ（神经元特异性）。然而，关于无脊椎动物烯醇化酶一级序列的信息很少。在这里，我们报告了从鱿鱼（Loligo pealii）神经系统中分离出两个重叠的cDNA克隆以及该酶的推定一级结构。这些cDNA克隆的复合序列为1575 bp，包含整个编码区（1302 bp），以及分别为66 bp和207 bp的5'和3'非翻译序列。烯醇化酶一级结构的跨物种比较表明，鱿鱼烯醇化酶与该酶的脊椎动物形式具有超过70%的序列同一性。序列相似性最高的是人类同源物的α同工型。Northern分析结果显示有一个单一的1.6 kb mRNA种类，其在不同组织中的相对丰度相差约10倍。有趣的是，原位杂交和聚合酶链反应实验的证据表明，编码烯醇化酶的mRNA存在于鱿鱼的巨轴突中。
