Abstract
Two groups of uremic peptides having 5 to 17 amino acids residues, one of which is composed of 20 peptides in total and the other of 16 peptides in total, were isolated respectively from two groups of hydrophobic middle molecule fractions in the hemofiltrates of two dialysis patients by the ion exchange separation into acidic, neutral and basic portions, followed by the adsorption of middle molecule substances on non-polar copolymer, and hydrophobic fractionation by HPLC. Uremic peptides were obtained universally from each hydrophobic fraction. These peptides are abundunt in glutamic acid, aspartic acid, threonine or serine and especially in glycine, while scarce in aromatic amino acids. A common characteristic of these peptides is their amino acid proportion with abundunt residues of hydrophilic amino acids and glycine. A significant difference of the hydrophobicity value against one glycine residue was observed between uremic and biologically active peptides. It seems that these uremic peptides do not conjugate with any plasma components and permeate into body cell. Therefore, it seems reasonable to assume that these peptides play an important role in patients with uremia.
