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首页> 外文期刊>Neurochemistry International: The International Journal for the Rapid Publication of Critical Reviews, Preliminary and Original Research Communications in Neurochemistry >A new type of neuron-specific aminopeptidase NAP-2 in rat brain synaptosomes.
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A new type of neuron-specific aminopeptidase NAP-2 in rat brain synaptosomes.

机译：大鼠脑突触小体中一种新型的神经元特异性氨肽酶NAP-2。

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摘要

A novel neutral aminopeptidase (NAP-2) was found exclusively in the rat central nervous system (CNS). It was separated from the ubiquitous puromycin-sensitive aminopeptidase (PSA) and the neuron-specific aminopeptidase (NAP) by an automated FPLC-aminopeptidase analyzer. The activity of the neuronal aminopeptidase enriched in the synaptosomes is different from NAP and PSA in distribution and during brain development. The enzyme was purified 2230-fold to apparent homogeneity from rat brain cytosol with 4% recovery by ammonium sulfate fractionation, followed by column chromatography successively on Phenyl-Sepharose, Q-Sepharose, Sephadex G-200, and Mono Q. The single-chain enzyme with a molecular mass of 110kDa has an optimal pH of 7.0 and a pI of 5.6. It splits beta-naphthylamides of amino acid with aliphatic, polar uncharged, positively charged, and aromatic side chain. Leucyl beta-naphthylamide (Leu betaNA) is the best substrate with the highest hydrolytic coefficiency followed by Met betaNA=Arg betaNA=Lys betaNA>Ala betaNA>Tyr betaNA>Phe betaNA. The cysteine-, metallo-, glyco-aminopeptidase releases the N-terminal Tyr from Leu-enkephalin with a K(m) 82microM and a k(cat) of 1.08s(-1), and Met-enkephalin with a K(m) of 106microM and a k(cat) of 2.6s(-1). The puromycin-sensitive enzyme is most susceptible to amastatin with an IC(50) of 0.05microM. The data indicate that the enzyme is a new type of NAP found in rodent. Its possible function in neuron growth, neurodegeneration, and carcinomas is discussed.
机译：仅在大鼠中枢神经系统（CNS）中发现了一种新型的中性氨基肽酶（NAP-2）。通过自动化的FPLC-氨基肽酶分析仪将其与遍在的嘌呤霉素敏感性氨基肽酶（PSA）和神经元特异性氨基肽酶（NAP）分离。在突触小体中富集的神经元氨肽酶的活性在分布和大脑发育过程中与NAP和PSA不同。将该酶从大鼠脑细胞溶质中纯化2230倍至表观同质性，并通过硫酸铵分级分离回收4％，然后依次在苯基-Sepharose，Q-Sepharose，Sephadex G-200和Mono Q上进行柱色谱分析。分子量为110kDa的酶的最佳pH值为7.0，pI为5.6。它用脂肪族，极性不带电，带正电和芳香族侧链拆分氨基酸的β-萘酰胺。亮氨酰β-萘酰胺（Leu betaNA）是具有最高水解效率的最佳底物，其次为Met betaNA = Arg betaNA = Lys betaNA> Ala betaNA> Tyr betaNA> Phe betaNA。半胱氨酸，金属，糖基氨基肽酶从亮脑啡肽释放N末端酪氨酸，其K（m）为82microM，ak（cat）为1.08s（-1），而Met-脑啡肽释放为K（m） 106microM和ak（cat）为2.6s（-1）。嘌呤霉素敏感酶对阿马他汀最敏感，IC（50）为0.05microM。数据表明该酶是在啮齿动物中发现的一种新型NAP。讨论了其在神经元生长，神经变性和癌中的可能功能。

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