Yajima R, Chikuma T, Kato T
Research Institute, Dainabot Co. Ltd., Matsudo, Japan.
J Neurochem. 1994 Sep;63(3):997-1002. doi: 10.1046/j.1471-4159.1994.63030997.x.
Using the highly sensitive HPLC-fluorophotometry technique, anterograde and retrograde axonal transport of carboxypeptidase H (CPH), a putative prohormone processing enzyme that removes a basic amino acid from the C-terminus of a precursor peptide, was measured 12-72 h after double ligations of rat sciatic nerves. CPH-like activity in rat sciatic nerves was 60-fold lower than that in the pituitary gland. CPH-like enzyme activity was rapidly accumulated in the proximal segment and peaked 48 h after ligation. The axonal flow was 100 mm/day, indicating that CPH in rat sciatic nerves is rapidly transported to the nerve terminals as an active form. The properties of the enzyme were similar to those of CPH in the brain: The pH optimum is at 5.5, and the molecular mass is approximately 5 kDa. These results suggest that active CPH in the PNS is transported by a rapid anterograde axonal flow and may play a role in converting proneuropeptides to active neuropeptides under the axonal transport.
运用高灵敏度的高效液相色谱-荧光光度法技术，在大鼠坐骨神经进行双重结扎12至72小时后，对羧肽酶H（CPH）的顺行和逆行轴突运输进行了测定。羧肽酶H是一种假定的激素原加工酶，可从前体肽的C末端去除一个碱性氨基酸。大鼠坐骨神经中的CPH样活性比垂体中的低60倍。CPH样酶活性在近端段迅速积累，并在结扎后48小时达到峰值。轴突运输速度为每天100毫米，这表明大鼠坐骨神经中的CPH以活性形式迅速运输到神经末梢。该酶的特性与脑中的CPH相似：最适pH值为5.5，分子量约为5 kDa。这些结果表明，外周神经系统中的活性CPH通过快速的顺行轴突运输进行转运，并且可能在轴突运输过程中在将前神经肽转化为活性神经肽方面发挥作用。
