Koyama I, Fujimori-Arai Y, Hirota N, Sakai T, Sakagishi Y, Komoda T
Department of Medical Technology, Junior College, Saitama Medical School, Japan.
Biochim Biophys Acta. 1991 Oct 25;1080(2):165-72. doi: 10.1016/0167-4838(91)90145-p.
Rabbit liver and kidney tissues are known to produce an intestinal-like alkaline phosphatase (IAP-like enzyme) as a dominant isozyme, with a minor isozyme of tissue-unspecific type (UAP), unlike humans and other mammalians. We investigated immunohistochemically and biochemically these unique isozymes in the rabbit liver and bone, and compared them with the human isozyme. In rabbit liver, UAP was found to be localized only in the apical part of the membrane of cells lining the bile duct, whereas IAP-like enzyme was found in the sinusoidal membrane of hepatocytes. Rabbit liver UAP was separated from IAP-like enzyme by DEAE-cellulose column chromatography. Rabbit bone tissue contained only one UAP isozyme. The two UAPs were biochemically and physicochemically compared with human liver AP. Both UAPs reacted with an anti-human liver AP monoclonal antibody, not with an anti-human bone AP monoclonal antibody, indicating that both enzymes have the same antigenicity as human liver AP. Rabbit liver and bone UAPs had similar N-linked sugar-chain heterogeneities to the respective human enzymes. In addition, rabbit bone AP also had an O-linked sugar chain, as did human bone AP, unlike rabbit and human liver APs.
与人类和其他哺乳动物不同，已知兔肝脏和肾脏组织会产生一种肠样碱性磷酸酶（IAP样酶）作为主要同工酶，还有一种组织非特异性类型（UAP）的次要同工酶。我们对兔肝脏和骨骼中的这些独特同工酶进行了免疫组织化学和生物化学研究，并将它们与人类同工酶进行了比较。在兔肝脏中，发现UAP仅定位于胆管内衬细胞的膜顶端部分，而IAP样酶则存在于肝细胞的窦状膜中。通过DEAE-纤维素柱色谱法将兔肝脏UAP与IAP样酶分离。兔骨组织仅含有一种UAP同工酶。将这两种UAP与人类肝脏碱性磷酸酶进行了生物化学和物理化学比较。两种UAP均与抗人肝脏碱性磷酸酶单克隆抗体反应，而不与抗人骨碱性磷酸酶单克隆抗体反应，这表明这两种酶与人类肝脏碱性磷酸酶具有相同的抗原性。兔肝脏和骨骼UAP与各自的人类酶具有相似的N-连接糖链异质性。此外，与兔和人类肝脏碱性磷酸酶不同，兔骨碱性磷酸酶与人骨碱性磷酸酶一样也具有O-连接糖链。
