Serum enzyme activity in the normal newborn infant.

The assay of serum enzymes has been used increasingly in recent years as an aid to clinical diagnosis and prognosis, but the literature contains few references to the exploitation of these laboratory tests in paediatrics. Following the development in these laboratories of assay procedures for glutamate-oxalacetate transaminase (GO-T), glutamate-pyruvate transaminase (GP-T), lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) suited to routine work, the determination of the normal serum activities of these enzymes in the neonatal period was undertaken in conjunction with an investigation of the usefulness of their estimation in haemolytic disease of the newborn. The transaminase enzymes form a link between protein and carbohydrate metabolism and mediate in the reactions shown in equations (i) and (ii).