Effect of Prematurity on the Developmental Progression from Fetal to Adult Thymidine Kinase in Human Serum

Abstract

The developmental progression of thymidine kinase from the electrophoretically slow-migrating ‘fetal’ forms to the fast-migrating ‘adult’ form was examined weekly in the serum of 5 premature infants. Only the fetal forms were present up to 32 weeks after conception. The adult form appeared along with the fetal forms until 39 weeks post-conception; thereafter, only the adult form was detected. With respect to post-conceptional age, the timing of the changeover from fetal to adult serum thymidine kinase was the same in the prematurely born infants as in stillborn infants at an equivalent gestational age.