The effect of various
amino acids and
MnCl2 on
prolinase activity in erythrocyte lysates from a healthy individual and a patient with
prolidase deficiency was investigated. A concentration of 0.1 mM
MnCl2 increased
prolinase activity in normal erythrocytes against
pro-gly, pro-glu,
pro-leu,
pro-ser and pro-phe, but inhibited that against pro-
ala, pro-val, pro-met and pro-asp. However,
prolinase activity against these iminodipeptides was enhanced by pre-incubation with
glycine, independent of
MnCl2. The same studies on erythrocytes from a
prolidase-deficient patient showed almost the same results as the normal control, except that
prolinase activity against
pro-gly and
pro-ser was slightly inhibited by adding 0.1 mM
MnCl2. Some
amino acids,
glutamic acid and
glutamine, slightly enhanced
prolinase activity against
pro-gly in erythrocytes from both the normal control and the
prolidase-deficient patient, but N-acetyl-
L-glutamic acid,
gamma-aminobutyric acid (
GABA) and
beta-alanine showed no effect. Branched
amino acids,
L-valine,
L-leucine and
L-isoleucine strongly inhibited the
prolinase activity against
pro-gly. However, conversely, their isomers, D-
valine, D-
leucine and D-
isoleucine, enhanced it. The kinetics of
prolinase activity in the erythrocytes from both the normal individual and the prolidasedeficient patient were also studied. Their Km values were changed by adding
glycine or 0.1 mM
MnCl2, but Vmax values were almost the same.