Uptake of protein by mammalian cells: an underdeveloped area. The penetration of foreign proteins into mammalian cells can be measured and their functions explored.

摘要: Although it is accepted on the basis of biological and morphological evidence that mammalian cells will take up macromolecules, little known about kinetics, specificity, functions this uptake. With labeled proteins used as models, found transport proceeds at very low rates, requires energy, markedly enhanced by polybasic compounds. Molecular charge size are important factors: clearly favor cationic macromolecules large molecular weights. Neither factor, however, can fully account for selectivity detected in uptake different proteins. Ingested albumin undergoes rapid extensive degradation. This fact suggests have only a limited chance to express their activity target cells, finding relevant also role foreign nucleic acids possibility achieving genetic transformation animal cells. There concrete indications, spite short half-life, act carriers, precursors active agents, regulators metabolic host They may be control growth differentiation. These exogenous still largely unexplored.