ACETYLCHOLINESTERASE SUBSTRATES, beta -METHYLCHOLINE ESTERS.
Technical rept. Jun 68-Feb 69,
EDGEWOOD ARSENAL MD
Pagination or Media Count:
ETA-Methylcholine proprionate I and i-butyrate II are good substrates for eel acetylcholinesterase AChE. Enzymatic hydrolysis of the corresponding pivalyl ester is barely detectable. For study of AChE under conditions where the blank hydrolysis rate of substrate must be reduced to a minimum. I and II can be used advantageously. Like acetylcholine and beta-methylcholine acetate, I shows substrate inhibition. The i-butyryl ester, II, gives no significant substrate inhibition. Kinetic constants for both enymatic and nonenzymatic hydrolysis are reported for the group of esters. Evidence is presented which suggest that the rate of acylation of the enzyme parallels reactivity with hydroxide ion for acetylcholine and the acetyl and propionyl esters of beta-methylcholine. With the i-butyryl ester of beta-methylcholine there is a relative decrease in enzymatic acylation rate. Author