Rothenberg S P, Quadros E V
Division of Hematology/Oncology, State University of New York Health Science Center Brooklyn 11203, USA.
Baillieres Clin Haematol. 1995 Sep;8(3):499-514. doi: 10.1016/s0950-3536(05)80218-5.
Transcobalamin II is a plasma protein that binds vitamin B12 (cobalamin) as it is absorbed in the terminal ileum and distributes it to tissues. The circulating transcobalamin II-cobalamin complex binds to receptors on the plasma membrane of tissue cells and is then internalized by receptor-mediated endocytosis. A number of genetic abnormalities are characterized either by a failure to express transcobalamin II or by synthesis of an abnormal protein. These disorders result in cellular cobalamin deficiency and megaloblastic anaemia. In this chapter we review the structural and functional properties of transcobalamin II, the receptor for the transcobalamin-cobalamin complex and the clinical disorders that are associated with perturbation of circulating transcobalamin II. In addition, we provide emerging data about the molecular genetics of transcobalamin II which has emanated from our own and other laboratories.
转钴胺素II是一种血浆蛋白，在维生素B12（钴胺素）于回肠末端被吸收时与之结合，并将其输送到各个组织。循环中的转钴胺素II - 钴胺素复合物与组织细胞膜上的受体结合，然后通过受体介导的内吞作用被内化。一些遗传异常的特征是无法表达转钴胺素II或合成异常蛋白质。这些疾病会导致细胞钴胺素缺乏和巨幼细胞贫血。在本章中，我们将综述转钴胺素II的结构和功能特性、转钴胺素 - 钴胺素复合物的受体以及与循环转钴胺素II紊乱相关的临床疾病。此外，我们还提供了来自我们自己和其他实验室的有关转钴胺素II分子遗传学的新数据。
