title: Absence of any detectable activity of the membrane marker enzyme 5'-nucleotidase in human red blood cells.
abstract: We have investigated in human red blood cell membranes the presence of a 5'-nucleotidase, which is considered a general marker of plasma membranes. No activity was detectable with a highly sensitive colorimetric method. This absence is not due to the rapid decline of enzyme activity in the course of red cell ageing, nor to its release during membrane preparation; nor is it due to substrate accessibility hindrance to the active center of the enzyme. Thus, the ubiquitousness of 5'-nucleotidase in plasma membranes is questioned.
mesh_terms: D002462:Cell Membrane / Q000201:enzymology; D004910:Erythrocyte Membrane / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D009708:Nucleotidases / Q000097:blood*
chemical_list: D009708:Nucleotidases