Amino acid composition of rat and human liver microsomes in normal and pathological conditions

The amino acid composition of proteins from liver microsomes has been studied in rats and in human subjects with normal liver, with obstructive jaundice or liver cirrhosis. The pattern of the amino acid composition of microsomes appeared to be species-specific. Phenylalanine, threonine, serine, proline, histidine and [aspartic acid plus asparagine] were increased, while alanine, tyrosine, glycine and arginine were decreased in the human compared to the rat microsomes. In patients with obstructive jaundice of short duration (less than two months) only a slight decrease in leucine and phenylalanine could be noticed, while in the case of liver cirrhosis amino acid composition was markedly changed.