Effect of Poly-L-arginine on Rate of Bovine IgG Transport by Newborn Pig Intestine

Abstract

MOVEMENT of protein molecules within and across the plasma membranes of mammalian cells probably occurs more widely than is generally realized. Examples of protein transport that are not normally considered in the same light include the supposed movement of “carrier” proteins within the plasma membrane¹, the penetration of albumin into isolated tumour cells² and the endocytosis of proteins by the epithelium of the small intestine³. Yet the protein–membrane interactions which probably accompany the movement of protein molecules in each case are likely to have certain features in common. For example, transported protein must show some temporary affinity for constituents of the membrane, and the actual movement of protein across the membrane will cause some distortion of otherwise stable structures. The experiments described here were designed to test whether the transport of protein by the pig intestinal mucosa was in any way similar to the transport of protein into tumour cells, a system which has been used extensively to study some of the macromolecular interactions associated with protein transport².