Manometric and spectrophotometric procedures for measurement of procaine hydrolysis by mouse liver in vitro

A decrease in absorbance at 313 nm was used to determine procaine hydrolysis by mouse liver. Results suggested that procaine hydrolysis was not linearly dependent upon the amount of tissue added to the incubate. This resulted from the fact that p-aminobenzoic acid, one of procaine's hydrolysis products, also absorbed at 313 nm. A dual wavelength analysis procedure is described which permitted accurate measurement of procaine hydrolysis by mouse liver without physical separation of procaine from its hydrolysis products. Measurements by the dual wavelength and manometric methods of inhibition of procaine hydrolysis in livers from mice treated with triorthotolyl phosphate indicated that both methods yielded quantitatively comparable results. The dual wavelength procedure is recommended for future studies of procaine hydrolysis by mammalian tissues.