Expression and Activity of the Ca2+-ATPase Enzyme in Human Neonatal Erythrocytes

Abstract

The plasma membrane Ca²⁺-ATPase (PMCA) is one of the main regulators of Ca²⁺ homeostasis. We studied the perinatal alteration of the abundance and the activity of PMCA molecules in human erythrocytes in pre-term and full-term neonates and children at the age of 1–4 years. The lower abundance of the 4b isoform was associated with lower enzyme activity in full-term neonates compared to children. Although the number of PMCA molecules was higher in pre-term neonates, their total PMCA activities were identical to those of full-term neonates. Our findings suggest that the abundance of PMCA molecules changes during the perinatal development. The same activity at higher enzyme molecule numbers might indicate a potential immaturity of the enzyme in the pre-term infant.