Red cell enzymopathies in the newborn. I. Evaluation of red cell metabolism
Travis, S.F.; Delivoria-Papadopoulos, M.
Annals of Clinical and Laboratory Science 12(2): 89-98
1982
ISSN/ISBN: 0091-7370 PMID: 6280578 Document Number: 193991
The age-dependent red cell glycolytic enzymes (hexokinase, aldolase, pyruvate kinase) and glucose-6-phosphate dehydrogenase and most glycolytic intermediates are elevated at birth and at 11-12 mo. of age, consistent with the presence of a young red cell population the entire 1st yr of life. However, certain red cell enzymes are elevated out of proportion to the age of the red cell population [phosphoglucose isomerase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase (PGK) and enolase (ENO)] whereas others are decreased [phosphofructokinase (PFK), glutathione peroxidase, carbonic anhydrase, etc.]. These metabolic characteristics are felt to be unique and representative of fetal erythropoiesis. Activities of PGK and ENO decrease and PFK increases toward normal adult values beginning at 8-9 wk of age. The concentration of G-6-P steadily increases after birth and peaks at 3-4 wk of age, at a time when PFK activity remains relatively unchanged, suggesting a relative block in glycolysis at the PFK step secondary to an enzyme with both decreased activity and altered kinetic properties (a fetal isozyme). Evaluation of red cell enzyme and glycolytic intermediate data obtained in the 1st yr of life should be related to the knowledge that a young red cell population is present and the characteristic unique metabolic red cell alterations described in cord blood persist beyond the immediate neonatal period.