The preparation, properties, and metabolism of 14C-bicarbonate-labelled transferrin |
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Authors: | J Martinez-Medellin H M Schulman |
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Institution: | Lady Davis Institute for Medical Research Jewish General Hospital, Montreal, Canada. |
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Abstract: | 14C-bicarbonate-labelled transferrin was prepared in order to study the role of bicarbonate in the cell-mediated release of iron from transferrin. 14C-bicarbonate bound to transferrin only in the presence of iron and with a ratio of bound bicarbonate to bound iron of one. The transferrin-14C-bicarbonate complex was very stable in Tris-HCl buffered at pH 7.5–9.0 even in the presence of excess non-radioactive bicarbonate. However, oxalate, citrate, and phosphate promoted a rapid exchange of transferrin-bound 14C-bicarbonate with bicarbonate present in the medium.Rabbit reticulocytes effected a temperature-dependent release of 14C-bicarbonate from transferrin at the same rate at which they incorporated 59Fe from transferrin — suggesting the existence of a coordinated mechanism in the cells for the release of both iron and bicarbonate from transferrin. |
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Keywords: | To whom correspondence should be addressed |
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