Studies on Cholinesterase

Abstract

In the first report (published elsewhere), we studied the distribution of the cholinesterase (ChE) in the human brain. In this report, we studied the ChE in the human serum. According to the recent literatures on ChE, the physiological role of the non-specific or pseudo-ChE in the serum is not so clear as the specific or true ChE in the nervous tissue. While the latter is one of the important substances for the normal function of the nerve, it is not determined whether the pseudo-ChE in the serum is in dispensable or not for the normal metabolism of the body. Despite these facts, the presence of the definite relationship between serum ChE and liver made it clinically important to study the level of ChE in the serum. Furthermore, there may be some correlation, though indirect, between the serum ChE and the neuro-humoral function of the body. In this research, we studied the ChE level of the normal and of patients of liver, tumor, tuberculosis and other various diseases. Method As in the first report, the method of Ammon1) using the Warburg's apparatus was employed. The serum was diluted 50 times with the Ringer's solution with, 0.025M sod. bicarbonate. As substratum, acetyl choline chloride (Ach) (Roche) was used. After equilibrium was attained, Ach solution in the side arm was poured into the main, part, which con tamed the serum diluted with Ringer's, solution. Final concentration of Ach was 0.25% (0.015M). Though this concentration is not the optimal one for the maximal activity of the serum ChE, it was convenient to use this concentration for measuring the ChE of serum and nervous tissue simultaneously. A few minutes after mixing, reading was taken and repeated after 10 and 20minutes. The activity of ChE was expressed 87