Comparison of X-prolyl dipeptidyl-aminopeptidase activity in human cerebrospinal fluid with that in serum.

X-Prolyl dipeptidyl-aminopeptidase activities in cerebrospinal fluid and serum from the same patients without neurological diseases, undergoing surgery under lumbar anesthesia, were assayed fluorometrically with a newly synthesized fluorogenic substrate, 7-glycylproline-4-methylcoumarinamide; the values were 129.1 +/- 19.5 nmoles/min/l and 54.17 +/- 3.11 mumoles/min/l (mean +/- SEM, n = 23), respectively, and there was no correlation between both activities (r = 0.0894).