Studies on the kinetic properties and subcellular localization of adenine nucleotide phosphatases in peripheral blood lymphocytes from control subjects and patients with common variable primary hypogammaglobulinaemia.
Specific assays for 5'-nucleotidase, adenosine diphosphatase (ADPase) and Mg2+-dependent adenosine triphosphatase (Mg2+-ATPase) have been optimized for human lymphocytes and their subcellular localizations determined by sucrose density gradient centrifugation. 5'-Nucleotidase was localized solely to the plasma membrane of the lymphocyte. ADPase activity has been shown to have a dual localization to the plasma membrane and mitochondria, whilst Mg2+-ATPase was mainly located in the mitochondria. No [Na+,K+] activated Mg2+-dependent ATPase could be measured in these cells. We have confirmed the striking decrease in the specific activity of 5'-nucleotidase activity in lymphocytes from patients with common variable primary hypogammaglobulinaemia. In contrast, the specific activities of ADPase and Mg2+-ATPase showed no alteration in lymphocytes from the patient group when compared to controls. Thus the deficiency of ecto-5'-nucleotidase in the lymphocytes of patients with hypogammaglobulinaemia is a highly selective defect in purine metabolism.
D015720:5'-Nucleotidase; D000251:Adenosine Triphosphatases / Q000097:blood*; D000361:Agammaglobulinemia / Q000201:enzymology*; D001081:Apyrase / Q000097:blood*; D017301:Ca(2+) Mg(2+)-ATPase; D002462:Cell Membrane / Q000201:enzymology; D002500:Centrifugation, Isopycnic; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology; D009708:Nucleotidases / Q000097:blood*; D010744:Phosphoric Monoester Hydrolases / Q000097:blood*
D009708:Nucleotidases; D010744:Phosphoric Monoester Hydrolases; D015720:5'-Nucleotidase; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D001081:Apyrase