Implication of lysine residues in the loss of 6-phosphogluconate dehydrogenase activity in aging human erythrocytes.
The activity of 6-phosphogluconate dehydrogenase (6-PGDH) decreases in aged human erythrocyte populations. The aged enzyme has 11 lysine residues less than the young enzyme, when they are measured with 2,4,6-trinitro-benzenesulfonic acid (TNBS). Treatment of young enzyme with ascorbate for 15 min produces the loss of 8 lysine residues and the diminution of enzymatic activity. These results suggest that there is a modification of lysine residue in human erythrocytes during senescence, probably caused by oxidation. This modification of lysine residue could imply the loss of enzymatic activity. This result is similar to that found in rat liver 6-PGDH during aging, described previously (Gordillo et al., J. Biol. Chem. 264 (1989) 17014-17019).
Departamento de Bioquimica, Facultad de Farmacia, Universidad de Sevilla, Spain.
E
E
Gordillo
A
A
Machado
D000328:Adult; D004350:Drug Residues / Q000032:analysis / Q000494:pharmacology*; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007158:Immunologic Techniques; D008239:Lysine / Q000032:analysis / Q000494:pharmacology*; D008875:Middle Aged; D010734:Phosphogluconate Dehydrogenase / Q000032:analysis / Q000097:blood*
D010734:Phosphogluconate Dehydrogenase; D008239:Lysine