Complete amino acid sequence of the neurone‐specific γ isozyme of enolase (NSE) from human brain and comparison with the non‐neuronal α form (NNE)

Abstract

The complete amino acid sequence (433 residues) of the human neurone-specific y isozyme of enolase (NSE) has been determined by a combination of direct amino acid sequencing and nucleotide sequencing of cloned cDNA. Substantial amino acid sequence of the non-neuronal a form of the enzyme was also obtained which agreed almost entirely with the indirect cDNA sequence [9]. Comparison of the two human sequences shows no insertions or deletions, but 72 replacements. Comparison of the human y form with the corresponding isozyme from the rat shows only 7 replacements (compared to 27 changes between the human and rat a isozymes). We have identified regions of sequence difference between the human c( and y forms that are mainly hydrophilic in character (residues 271 -285,298-316 and 416-433). These residues are on the surface of the three-dimensional structure [21] and could be useful as immunogens to produce antibodies specific for the neurone-specific form.The glycolytic enzyme enolase (2-phospho-~-glycerate hydrolyase), which catalyses the interconversion of 2-phosphoglycerate and phosphoenolpyruvate, occurs in three homologous but distinct isozymic forms a, fl and y [l, 21. The active enzyme is a dimer of non-covalently linked subunits ( M , 47000) that can also form heterodimers [3]. The a and B subunits are found in many tissues, the p subunit being predominant in muscle, whereas the enzyme from brain contains either a or y subunits. The y form is found only in neurones and neuroendocrine tissue; this has led to the y form being designated as neurone-specific enolase (NSE) and the a form as non-neuronal enolase (NNE). Considerable interest has focussed upon the tissue specificity of enolase, and on the control of its expression. The y isozyme is of medical interest because it is found in elevated concentrations in the plasma of patients suffering from tumors with neuroendocrine features such as neuroblastoma [4] or small-cell carcinoma of the lung [5]. Comparative structural studies can reveal potential epitopes that could facilitate the production of monoclonal antibodies able to distinguish the y form specifically which could have useful application as analytical and diagnostic reagents.The amino acid sequences of the a and y forms of the rat isozymes have been determined by cDNA sequencing [6 -81, as has that of the human a isozyme [9]. Direct amino acid sequencing gave the sequence of the chicken muscle fl isozyme[lo] which is one of the forms together with the yeast 1 form [I 1,221 that have given crystals suitable for X-ray crystallography. Two yeast isozymes [ 121 and a non-neuronal-like enolase from Xenopus luevis [13] techniques. We report here the results of amino acid and cDNA sequencing of the human y isozyme which together have determined the complete sequence of this isozyme. Comparison with the sequence of the CI isozyme has allowed us to identify regions of potential immunogenic difference which may help in the production of antibodies capable of discriminating between these two human isozymes. M...

Rauwolfia vomitoria and Gongronema latifolium extracts influences cerebellar cortex

“…NSE is a cytosolic protein that functions as brain-specific glycolytic enzyme, and plays an important role in intracellular energy metabolism [48]. It is expressed by mature neurons and cells of neuronal origin, and thus regarded as a marker of the neuronal state [49,50], but becomes markedly expressed after brain injury [51]. It is reported that RV cause neuronal injury [20,22], and this may be a reason for the marked expression of the enolase, which may be deleterious to the normal function of the cerebellar cortical cells.…”

Enolase and Arrestin are Novel Nonmyelin Autoantigens in Multiple Sclerosis

“…Although there was a higher prevalence of positive proliferative responses against NSE in MS patients compared to that in controls, we did not find any difference in proliferative responses against NNE. Enolase is a glycolytic enzyme (2-phospho-D-glycerate hydrolase), which exists in three isoforms: α-enolase or NNE, which is ubiquitous, β-enolase, which is predominant in muscle, and γ-enolase of NSE, which is found in neurons, paraneuronal cells, and neuroendocrine cells (38,39). Recently, the important contribution of neurodegeneration to the pathogenesis of MS has been appreciated (40,41).…”

Molecular structure of the human muscle-specific enolase gene (ENO3)

“…la and lb). Additionally, at these stringencies cDNA probes representing the N-or C-terminus of NSE [9] identified XbaI fragments of 5 kb and 0.8 kb respectively on Southern blots of AHGME (results not shown). The map of AHGME is shown in Fig.…”

“…Fragments derived from human NSE cDNA [9] and human NNE cDNA [8,10] were labelled by random priming for use as probes, as were genomic fragments derived from the clone AHGME described here. The latter probes were pre-reannealed with excess total human DNA prior to use [31].…”

“…Three major tissue-specific isoforms of enolase have been identified in mammals and birds, y or neuron-specific enolase (NSE), expressed primarily in neurons, /J or musclespecific enolase (MSE), expressed in striated muscle, and a or non-neuronal enolase (NNE), expressed in foetal cells and other adult cell types. Detailed structural information concerning rat and human NSE and NNE has emerged from cDNA cloning [5][6][7][8][9][10][11], reaffirming the existence of three separate genes, of which only the rat NSE gene has been characterized so far [12]. The human gene loci have been named ENO] (NNE), EN02 (NSE) and EN03 (MSE), and chromosome in situ hybridization data are also suggestive of at least three loci [13].…”