ABSTRACT
Most patients who depend on an i.v. alimentation can be supplied adequately with protein by means of crystalline amino acid mixtures in aqueous solutions. Protein synthesis of the body requires all the amino acids serving as building blocks simultaneously. Consequently, the entire supply of both the essential and the nonessential amino acids are fundamental for a functioning protein synthesis and the maintenance of nitrogen balance. In in vitro studies, hydrolytic susceptibilities of certain peptides and acetylated amino acids were investigated in various organs of rats. The results show the potential to hydrolyze these substances and the ubiquitous hydrolase activities in tissues. The utilization of several amino acid derivates was tested in a rat experimental model during long-term parenteral nutrition by means of nitrogen-balance and weight-gain studies. Both acetylated amino acids and dipeptides were efficiently utilized for nitrogen retention and growth.
