TY - JOUR T1 - CHOLINE-ESTERASE ACTIVITY OF NORMAL AND PATHOLOGICAL HUMAN SERA JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 34 LP - 42 VL - 59 IS - 1 AU - G. E. HALL AU - C. C. LUCAS Y1 - 1937/01/01 UR - http://jpet.aspetjournals.org/content/59/1/34.abstract N2 - 1. A micro-modification of the continuous titration method for the determination of the rate of hydrolysis of acetylcholine by blood serum is described. The choline-esterase activity is defined in terms of initial velocity of the hydrolysis. The unit chosen is the amount of enzyme necessary to liberate 1.00 cc. 0.01 n acetic acid in 10 minutes at pH 8.0 and 37.5°C. 2. The choline-esterase activity of a large number of normal and pathological human sera has been determined. The variation within the species is from 0.9 to 3.9 units per cubic centimeter, the mode being in the interval 2.4 to 2.6. Roughly three-quarters of the bloods examined had serum activities between 1.8 and 3.2. 3. No correlation between the choline-esterase activity of the serum and age, sex, activity, diet, heart-rate or blood-pressure could be found in either the normal or pathological group. None of the clinical conditions studied produced any characteristic change in the activity of this serum enzyme. ER -