Effects of amino acids and its metabolites on prolidase activity against various iminodipeptides in erythrocytes from normal human and a patient with prolidase deficiency

Abstract

The characteristics of prolidase in erythrocytes from controls and patient with prolidase deficiency were investigated. The erythrocytes were isolated from the heparinized blood of normal human and a patient with prolidase deficiency. Effects of various amino acids and their metabolites on prolidase activity against iminodipeptides in presence of 1 mmol/l MnCl(2) were investigated. Prolidase activity against glycylproline in erythrocytes from normal human was strongly enhanced by glycine, L-alanine, L-serine with MnCl(2), but the activity was strongly inhibited by L-valine, and L-leucine. However, the stereoisomers, D-leucine and D-valine enhanced the activity. The prolidase activity against methionylproline in erythrocytes from the patient with prolidase deficiency was also enhanced by glycine, L-alanine and L-serine. The activity was inhibited by l-leucine, but D-leucine and L-valine enhanced the activity against various iminodipeptides. Prolidase activity against glycylproline in normal human erythrocytes and against methionylproline from the prolidase-deficient patient was enhanced strongly by glycine, alanine and serine with MnCl(2). However, this activity was inhibited by L-leucine, but was enhanced by D-leucine.