title: Circulatory clearance, internalization, and degradation of muscle AMP aminohydrolase.
abstract: Chicken muscle AMP aminohydrolase is cleared rapidly from the circulation of chickens after intravenous injection of the purified enzyme (Husic, H. D., and Suelter, C. H. (1980) Biochem. Biophys. Res. Commun. 95, 228-235). After the intravenous injection of unlabeled, 125I-labeled, or [14C]sucrose-labeled AMP aminohydrolase, enzyme activity and radioactivity are cleared at the same rates and concentrate in the liver and spleen. After injection of the [14C]sucrose-labeled enzyme, 14C is retained in the liver and spleen and low molecular weight 14C is recovered primarily in a fraction which cosediments with lysosomes when tissue homogenates are sedimented on sucrose density gradients. When liver cells are fractionated after clearance of [14C]sucrose-labeled enzyme, 14C is recovered primarily in the parenchymal cells. The circulatory clearance of AMP aminohydrolase is inhibited by heparin and other sulfated polysaccharides, but not by compounds which inhibit previously described carbohydrate-mediated systems for the uptake of circulatory glycoproteins. Heparin injection after the clearance of AMP aminohydrolase causes the release of the enzyme from the liver and spleen into the circulation. When heparin is injected at various times after clearance, decreasing amounts of enzyme are released with time; these results show that the enzyme is internalized with a half-life of 0.98 h.
mesh_terms: D000659:AMP Deaminase / Q000378:metabolism*; D000818:Animals; D002250:Carbon Radioisotopes; D002645:Chickens; D007457:Iodine Radioisotopes; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D009132:Muscles / Q000098:blood supply / Q000201:enzymology*; D009709:Nucleotide Deaminases / Q000378:metabolism*; D012039:Regional Blood Flow; D013154:Spleen / Q000201:enzymology; D013997:Time Factors
chemical_list: D002250:Carbon Radioisotopes; D007457:Iodine Radioisotopes; D009709:Nucleotide Deaminases; D000659:AMP Deaminase