IMMUNOCYTOCHEMICAL LOCALIZATION OF ENDOPEPTIDASE 24.15 IN RAT-BRAIN
IMMUNOCYTOCHEMICAL LOCALIZATION OF ENDOPEPTIDASE 24.15 IN RAT-BRAIN
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DOI：
10.1016/0006-8993(92)90517-d
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发表时间：
1992-01-31
期刊：
影响因子：
2.9
通讯作者：
ORLOWSKI, M
中科院分区：
文献类型：
--
作者：
HEALY, DP;ORLOWSKI, M
肽链内切酶 24-15（EC 3.4.24.15；EP 24.15）是一种在大鼠睾丸、大脑和垂体中高度活跃的锌金属肽链内切酶，可将一些强啡肽原和脑啡肽原衍生的寡肽转化为相应的脑啡肽，并降解多种生物活性肽，包括缓激肽、神经降压素以及血管紧张素 I 和 二.使用在兔子中产生的针对从大鼠睾丸中分离的酶的均质制剂的多克隆抗体，在大鼠脑中研究了该酶的免疫细胞化学定位。 EP 24.15 免疫反应性在大脑中分布广泛，存在于神经元和神经胶质细胞中。然而，令人惊讶的是，根据生化证明，EP 24.15 活性主要与脑匀浆的可溶性蛋白部分相关，染色主要是细胞核，而不是细胞质。在大神经元中检测到细胞质染色，但强度不如核染色。在小脑浦肯野细胞和海马齿状回细胞的细胞核中检测到最高密度的 EP 24.15 染色。在含有已知为体外酶底物的肽的大脑区域中也发现了高水平的免疫反应性。这种定位支持 EP 24.15 在神经肽代谢中的作用，但也表明其在核功能中的作用尚未明确。
Endopeptidase 24-15 (EC 3.4.24.15; EP 24.15), a zinc-metalloendopeptidase highly active in rat testes, brain and pituitary, converts some prodynorphin- and proenkephalin-derived oligopeptides into the corresponding enkephalins and degrades a variety of bioactive peptides including bradykinin, neurotensin, and both angiotensin I and II. The immunocytochemical localization of the enzyme was studied in rat brain using a polyclonal antibody raised in rabbits against a homogeneous preparation of the enzyme isolated from rat testes. The distribution of EP 24.15 immunoreactivity in the brain was widespread, being present in both neurons and glial cells. Surprisingly, however, staining was predominantly nuclear, and not cytoplasmic as expected based on the biochemical demonstration that EP 24.15 activity is predominantly associated with the soluble protein fraction of brain homogenates. Cytoplasmic staining was detected in large neurons but was less intense than the nuclear staining. The highest density of EP 24.15-staining was detected in nuclei of cerebellar Purkinje cells and in hippocampal dentate gyrus cells. High levels of immunoreactivity were also noted in brain areas which contain peptides known to be substrates of the enzyme in vitro. This localization supports a role for EP 24.15 in neuropeptide metabolism, but also suggests an as yet undefined role in nuclear function.