Cystic fibrosis liver sialyltransferase.

The activity of sialytransferase with regard to the glycoprotein substrates asialofetuin and asialo-ovine submaxillary mucin was determined in normal, pathological control, and cystic fibrosis liver homogenates. Cystic fibrosis and pathological livers have about 40% of the average normal specific activity for sialytransferase. Several properties of cystic fibrosis sialytransferase were investigated and compared to those of the normal liver enzyme (Alhadeff et al. 1977). The pH optima curves were similar, but cystic fibrosis sialyltransferase appears to be more thermolabile than the normal liver enzyme. Isoelectric focusing studies revealed that the three most basic forms of sialyltransferase which are found in normal livers are deficient or absent in most cystic fibrosis liver. The data suggest that altered glycoprotein-sialyltransferases may be present in cystic fibrosis livers, probably a secondary effect due to general liver pathology.