Effect of reductive lactosamination on the hepatic uptake of bovine pancreatic ribonuclease A dimer.
Lactose has been coupled to the lysine residues of the cross-linked dimer of bovine pancreatic ribonuclease A by reductive amination with cyanoborohydride. Derivatives of ribonuclease dimer that contained up to 10 Nepsilon-1-(1-deoxylactitolyl)-lysine residues per molecule had greater than 75% of the enzymic activity of the unmodified enzyme toward yeast RNA. Upon intravenous injection of the 14C-labeled (enzymically inactivated by 14C-carboxymethylation) derivatives into rats, their uptake by the liver was a function of the number of lactose residues coupled. At 10 min, 69% of the injected derivative of ribonuclease dimer containing eight 1-deoxylactitolyl-lysine residues/molecule was found in the liver; with the non-glycosylated enzyme, the liver uptake at 10 min was only 4%, and 75% of the radioactivity was found in the kidneys.
D000818:Animals; D001692:Biological Transport; D002417:Cattle; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D007785:Lactose; D008099:Liver / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D010179:Pancreas / Q000201:enzymology*; D051381:Rats; D012260:Ribonucleases / Q000097:blood / Q000378:metabolism*
D012260:Ribonucleases; D007785:Lactose