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Plasma Turnover of 57 Cobalt‐Vitamin B 12 Bound to Transcobalamin I and II
Author(s) -
Hom B. L.
Publication year - 1967
Publication title -
scandinavian journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0036-553X
DOI - 10.1111/j.1600-0609.1967.tb01633.x
Subject(s) - vitamin b12 , cyanocobalamin , chemistry , in vitro , vitamin , plasma , endocrinology , medicine , biochemistry , biology , physics , quantum mechanics
The plasma turnover of radioactive vitamin B 12 bound in vitro to each of the two plasma binders (transcobalamins) was studied after intravenous injection. The observed T 1/2 values for the radioactive B 12 were 9–10 days when bound to transcobalamin I and about 1.5 hours when bound to transcobalamin II. In both cases, the plasma curves yielded similar final slopes, corresponding to T 1/2 values of 9.3 and 9.8 days. In the study with transcobalamin II, this is shown to be due to rapid reappearance in the plasma of the radiocobalt label bound to transcobalamin I.