Transferase activity of horse blood serum cholinesterase at hydrolysis of 1-methyl-8-acetoxychinolinium iodide in the presence of aliphatic alcohols

Abstract

To check whether the horse blood serum butyrylcholinesterase expresses transferase activity at the complex ester hydrolysis in the presense of several low-molecular aliphatic alcohols, a study was performed with aid of the chromogenic substrate 1-methyl-8-acetoxychinolium whose phenolic hydrolysis product absorbs intensively at 445 nm, whereas the initial ester in this specter area practically does not absorb. This allowed measuring simultaneously the products of accumulation of both products of enzymatic hydrolysis: of acetic acid by the potentiometric, while of phenol--by the photometric method. Rates of formation of both products of enzymatic hydrolysis are practically equal in experiments with all studied alcohols. This indicates that horse blood serum butyrylcholinesterase under these experimental conditions does not catalize transfer of acetyl residue to the studied aliphatic alcohols, i. e. does not have transefase activity.