Narita Yuichi, Oda Sen-ichi, Moriyama Akihiko, Kageyama Takashi
Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Inuyama 484-8506, Japan.
Arch Biochem Biophys. 2002 Aug 15;404(2):177-85. doi: 10.1016/s0003-9861(02)00209-6.
Purification of pepsinogen B from dog stomach was achieved. Activation of pepsinogen B to pepsin B is likely to proceed through a one-step pathway although the rate is very slow. Pepsin B hydrolyzes various peptides including beta-endorphin, insulin B chain, dynorphin A, and neurokinin A, with high specificity for the cleavage of the Phe-X bonds. The stability of pepsin B in alkaline pH is noteworthy, presumably due to its less acidic character. The complete primary structure of pepsinogen B was clarified for the first time through the molecular cloning of the respective cDNA. Molecular evolutional analyses show that pepsinogen B is not included in other known pepsinogen groups and constitutes an independent cluster in the consensus tree. Pepsinogen B might be a sister group of pepsinogen C and the divergence of these two zymogens seems to be the latest event of pepsinogen evolution.
已实现从狗胃中纯化胃蛋白酶原B。胃蛋白酶原B激活为胃蛋白酶B可能通过一步途径进行，尽管速率非常缓慢。胃蛋白酶B可水解多种肽，包括β-内啡肽、胰岛素B链、强啡肽A和神经激肽A，对Phe-X键的裂解具有高度特异性。胃蛋白酶B在碱性pH下的稳定性值得注意，推测是由于其酸性较弱。通过各自cDNA的分子克隆首次阐明了胃蛋白酶原B的完整一级结构。分子进化分析表明，胃蛋白酶原B不包含在其他已知的胃蛋白酶原组中，并且在共有树中构成一个独立的簇。胃蛋白酶原B可能是胃蛋白酶原C的姐妹组，这两种酶原的分化似乎是胃蛋白酶原进化的最新事件。
