Murata M, Tsurutani M, Hagiwara S, Homma S
Department of Nutrition and Food Science, Ochanomizu University, Tokyo, Japan.
Biosci Biotechnol Biochem. 1997 Sep;61(9):1495-9. doi: 10.1271/bbb.61.1495.
The location of polyphenol oxidase (PPO) in cells of apple fruit was examined by immunohistochemistry and subcellular fractionation. In mature apple fruits, where vacuoles occupy most of the cells, PPO was detected immunochemically near the cell walls with use of anti-apple PPO antibodies. In cells of immature fruits and tissue culture, PPO was detected in organelles other than the vacuoles, probably in plastids. The plastid fraction was purified by density gradient ultracentrifugation, and the activities of PPO and marker enzymes of plastids were the highest in the plastids. Most apple PPO was in plastids, as are other plant PPOs, and some of the protein was solubilized and proteolyzed during ripening and storage.
通过免疫组织化学和亚细胞分级分离法研究了苹果果实细胞中多酚氧化酶（PPO）的定位。在成熟苹果果实中，液泡占据了大部分细胞，利用抗苹果PPO抗体通过免疫化学方法在细胞壁附近检测到了PPO。在未成熟果实细胞和组织培养中，在液泡以外的细胞器中检测到了PPO，可能存在于质体中。通过密度梯度超速离心法纯化了质体组分，质体中PPO和质体标记酶的活性最高。与其他植物PPO一样，大多数苹果PPO存在于质体中，并且在成熟和储存过程中一些蛋白质被溶解和蛋白酶解。
