The characterization of the uptake of avidin-biotin complex by HeLa cells.

HeLa cells have been shown to internalize the avidin-biotin complex. Adsorptive pinocytosis seems to be the mechanism of this uptake as seen by the requirements of energy and the integrity of the microtubular assembly. Pretreatment of HeLa cells with cycloheximide inhibits uptake and binding of the avidin-biotin complex. Scatchard plot of specific binding of avidin indicates a single type of binding with a Kd of approx. 55 pM with about 21,500 receptors/cell. The lack of inhibition of binding by simple carbohydrates indicates that binding is not through the oligosaccharide chain of avidin.