title: Absence of 5'-nucleotidase in porcine polymorphonuclear leucocyte membranes.
abstract: A fraction enriched in plasma membranes from porcine polymorphonuclear leucocytes, isolated by sucrose density centrifugation was shown to possess considerable AMP hydrolysing activity (150 nmol/min per mg protein). However all of this activity could be inhibited using excess p-nitrophenyl phosphate in the incubation medium. Furthermore the hydrolysis of AMP by the membrane was unaffected by the 5'-nucleotidase inhibitor alpha, beta-methyleneadenosine diphosphate and by the lectin concanavalin A, another potent inhibitor of 5'-nucleotidase. An antibody against mouse liver 5'-nucleotidase also did not inhibit the activity. These results suggest that the hydrolysis of AMP by porcine polymorph membranes is not accomplished by a specific 5'-nucleotidase and the necessity for distinguishing between true 5'-nucleotidase and non-specific phosphatase activity is discussed.
mesh_terms: D015720:5'-Nucleotidase; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D003208:Concanavalin A / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D009504:Neutrophils / Q000201:enzymology*; D009708:Nucleotidases / Q000097:blood*; D051381:Rats; D013552:Swine
chemical_list: D003208:Concanavalin A; D009708:Nucleotidases; D015720:5'-Nucleotidase