ABSTRACT
This chapter presents results of the in vitro and in vivo absorption and metabolic studies with amino acids in parallel to each other. It discusses models for description and evaluation of the experimental results. The chapter examines the concept of an oscillatory steady state and a technique for explicit modeling and models for transport of amino acids and protein synthesis proposed for simulating complex real systems in absorption and utilization of amino acids. The role of the amino acid side chain in influx across the mucosal membranes has been examined directly for Glycine, Alanine, Valine, Leucine, and Phenylalanine. The results strongly suggest that the affinity for binding increases with increasing hydrophobicity of the side chain. The simplest model to evaluate intestinal transport processes is that which uses Vmax and Kt parameters in order to describe the saturation effect of increasing substrate concentration upon the initial velocities of the process.
