Aspartate aminotransferase and pyruvate kinase activities in erythrocytes separated according to age by gradient centrifugation
Reverberi, R.; Ferrari, L.; Ferrari, R.; Galluccio, L.; Moretti, M.; Menini, C.
Haematologica 71(1): 13-16
1986
ISSN/ISBN: 0390-6078 PMID: 3084349 Document Number: 283483
Some erythrocyte enzyme activities, such as aspartate aminotransferase (AST) and pyruvate kinase (PK), are sensitive indicators of cell age. Unlike PK activity, the shape and slope of the regression curve of AST activity with respect to age are not known. Therefore, we separated the erythrocytes of 7 healthy subjects according to age by means of centrifugation on Percoll density gradients. In the fractions (N = 52) we measured AST and PK activities, as well as the mean corpuscular volume (MCV). The experimental data confirm that PK activity declines according to an exponential curve. The decline of AST activity also follows an exponential law, but the regression coefficient is significantly higher (P < 0.005). On the other hand, MCV, although significantly correlated with age, has a much lower regression coefficient. Therefore AST activity is a more sensitive indicator of erythrocyte age than PK activity, whilst MCV is of limited use in this respect.