Dipeptidyl-aminopeptidase II in human cerebrospinal fluid: changes in patients with Parkinson's disease.

By using a sensitive and specific method, DAP II activity was found in CSF. DAP II activity in CSF of control patients without neurological diseases was 0.416 +/- 0.141 (mean +/- SD) nmole/min/ml and was higher than DAP IV activity in CSF, 0.221 +/- 0.062 (mean +/- SD) nmole/min/ml. In contrast, DAP II activity in serum was 1.16 +/- 0.16 (mean +/- SD) nmole/min/ml and was lower than serum DAP IV activity [41.85 +/- 3.36 (mean +/- SD) nmole/min/ml]. This relatively high activity of DAP II in CSF compared with the activity of DAP IV in CSF together with recent histochemical evidence on the localization of DAP II in some neurons (7) suggests that CSF DAP II may be derived from the brain and may be a marker of some peptidergic neurons. DAP II activity in CSF of patients with Parkinson's disease was significantly increased, whereas DAP IV activity in CSF did not change significantly.