title: NAD glycohydrolase activities and ADP-ribose uptake in erythrocytes from normal subjects and cancer patients.
abstract: Erythrocytes from cancer patients exhibited up to fivefold higher NAD glycohydrolase activities than control erythrocytes from normal subjects and also similarly increased [14C] ADP-ribose uptake values. When [adenosine-14C] NAD was used instead of free [14C] ADP-ribose, the uptake was dependent on ecto-NAD glycohydrolase activity. This was reflected in the inhibition of ADP-ribose uptake from [adenosine-14C] NAD by Cibacron Blue. ADP-ribose uptake in erythrocytes appeared to be complex: upon incubation with free [14C] ADP-ribose, the radiolabel associated with erythrocytes was located in nearly equal parts in cytoplasm and plasma membrane. Part of [14C] ADP-ribose binding to the membrane was covalent, as indicated by its resistance to trichloroacetic acid-treatment. A preincubation with unlabeled ADP-ribose depressed subsequent erythrocyte NAD glycohydrolase activity and binding of [14C] ADP-ribose to erythrocyte membrane; but it failed to inhibit the transfer of labeled ADP-ribose to erythrocyte cytoplasm. On the other hand, incubation with [adenosine-14C] NAD did not result in a similar covalent binding of radiolabel to erythrocyte membrane. In line with this finding, a preincubation with unlabeled NAD was not inhibitory on subsequent NAD glycohydrolase reaction and ADP-ribose binding. ADP-ribose binding and NAD glycohydrolase activities were found also in solubilized erythrocyte membrane proteins and, after size fractionation, mainly in a protein fraction of around 45kDa-molecular weight.
authors.affiliation: Istanbul University, Istanbul Faculty of Medicine, Department of Biophysics Capa-Istanbul, Turkey. ialbeniz@istanbul.edu.tr
authors.forename: Işil
authors.initials: I
authors.lastname: Albeniz
authors.forename: Ozlem
authors.initials: O
authors.lastname: Demir
authors.forename: Rüstem
authors.initials: R
authors.lastname: Nurten
authors.forename: Engin
authors.initials: E
authors.lastname: Bermek
mesh_terms: D036541:ADP-ribosyl Cyclase / Q000097:blood*; D051997:ADP-ribosyl Cyclase 1; D000246:Adenosine Diphosphate Ribose / Q000097:blood*; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000097:blood*; D003593:Cytoplasm / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D008970:Molecular Weight; D009244:NAD+ Nucleosidase / Q000097:blood*; D009369:Neoplasms / Q000097:blood* / Q000201:enzymology
chemical_list: D015703:Antigens, CD; D008562:Membrane Glycoproteins; D000246:Adenosine Diphosphate Ribose; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1