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The vitamin B12-binding protein in human leukocytes

1966; Elsevier BV; Volume: 117; Issue: 1 Linguagem: Inglês

10.1016/0304-4165(66)90167-x

1872-8006

Kai Simons, Thomas Weber,

Virus-based gene therapy research

1. Human leukocytes bind vitamin B12 added in vitro at a rate of 8.9 mμg/107 cells. Purified peripheral lymphocytes bind about nine times less per cell. 2. A method is described for the purification of the leukocytic vitamin B12-binding trace protein. 3. Immunoelectrophoresis of the purified trace protein labelled with 57Co-labelled vitamin B12 gives a radioactive precipitate with anti-luekocyte, anti-gastric juice and anti-saliva sera. 4. The molecular weight of the binding protein has been estimated by gel filtration as about 115 000–117 000. 5. The vitamin B12-binding protein appears to be synthesized in the leukocytes, for incorporation of [14C]leucine into this protein can be demonstrated on vitro. This observation adds further support to the hypothesis that the granulocytes aer one source of vitamin B12-binding proteins (devoid of intrinsic factor activity) found in serum and in the digestive fluids.