Accession Number : AD0702876

Title :   ACETYLCHOLINESTERASE SUBSTRATES, beta -METHYLCHOLINE ESTERS.

Descriptive Note : Technical rept. Jun 68-Feb 69,

Corporate Author : EDGEWOOD ARSENAL MD

Personal Author(s) : Steinberg,George M. ; Mednick,Morton L. ; Rice,Robert E. ; Maddox,Jan P.

Report Date : FEB 1970

Pagination or Media Count : 16

Abstract : 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)

Descriptors :   (*HYDROLYSIS, *ACETYLCHOLINESTERASE), (*CHOLINES, HYDROLYSIS), REACTION KINETICS

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE