Methodology for identification of serum middle molecules.
Filtration through membranes with different nominal cut-off was used for isolation of middle molecule fractions from uremic serum. Comparison was made with test substances which in gel filtration did not show a regular relationship between molecular weight and partition coefficient. The XM50 membrane (cut-off 50,000 D) showed the highest permeability to middle molecules (greater than 84%) whereas CF50 (same cut-off) retained middle molecules to some extent if filtration was carried out only once. The UM05 membrane (cut-off 500 D) was highly permeable for small molecules less than 300 D, intermediary permeable for molecules between 300 and 1000 D and retained molecules between 1,100 and 1,350 D more efficiently. It is concluded that filtration through membranes is a suitable method for identification of middle molecules.
D002850:Chromatography, Gel / Q000379:methods; D006801:Humans; D008970:Molecular Weight; D009842:Oligopeptides / Q000097:blood; D014118:Toxins, Biological / Q000097:blood* / Q000302:isolation & purification; D014462:Ultrafiltration / Q000379:methods; D014511:Uremia / Q000097:blood*
D009842:Oligopeptides; D014118:Toxins, Biological; C026865:uremia middle molecule toxins