ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The two stages in the uptake of transferrin by rabbit reticulo-cytes were investigated using radioiodine-labeled rabbit transferrin and albumin. The first stage of rapid, temperature-insensitive uptake of transferrin was similar to albumin uptake: uptake of both proteins increased linearly with increasing protein concentration of the incubation medium up to at least 60 mg/ml, was maximal at low ionic strength and pH, and increased in the presence of basic polyamino acids. Transferrin uptake was in part dependent on the reticulocyte concentration of the blood, but albumin uptake was independent of reticulocyte concentration.The second slower, temperature-sensitive stage of transferrin uptake was linearly related to reticulocyte concentration, and was not found with albumin, α1-macroglobulin or γ-globulin. Transferrin uptake was optimal at physiological pH and ionic strength and was unaffected by basic polyamino acids. When the transferrin concentration was raised, uptake increased to reach a maximum at a concentration of 15 mg/ml.It was concluded that the first stage of transferrin uptake was in part or wholly due to non-specific adsorption of transferrin to erythrocytes, while the second stage of uptake was specific for transferrin and reticulocytes and depended upon normal function of the cells.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1040770312
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