title: Rat plasma clearance rate and organ distribution of beta-hexosaminidase isoenzymes from human serum.
abstract: beta-Hexosaminidase (EC 3.2.1.30) is markedly increased in human serum in liver disease, chronic alcoholism, and pregnancy. Knowledge of the clearance rate of plasma/serum beta-hexosaminidase is necessary to evaluate this increase. We studied the plasma clearance of beta-hexosaminidase isoenzymes (purified from human serum and placenta) after their infusion into rat circulation. A recently developed enzyme immunoassay method was used to measure the human beta-hexosaminidase isoenzymes; this method relies on both immunoreactivity and enzyme activity, so intact human isoenzymes were measured. In comparison with the placental isoenzymes (t1/2 less than 2 min), the serum forms showed a considerably slower clearance (t1/2 = 2-4 h). However, desialylation of the serum forms resulted in their rapid clearance (t1/2 less than 2 min). The organ localization of the enzyme eliminated from the circulation was investigated 24 h after infusion. Placental and native serum isoenzymes accumulated mainly in the liver and the spleen. Desialylated serum forms were almost exclusively localized to the liver.
authors.affiliation: Department of Clinical Chemistry, University Hospital, Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Isaksson
authors.forename: B
authors.initials: B
authors.lastname: Hultberg
authors.forename: T
authors.initials: T
authors.lastname: Jonung
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D001619:beta-N-Acetylhexosaminidases / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D001619:beta-N-Acetylhexosaminidases