Toyo Jozo Kabushiki Kaisha

Kokusan Chemical Works Limited

Tsutomu Hirata

Kunio Matsumoto

Susumu Watanabe

Akira Ohtsuka

Yoshitaka Kagimoto

Kiyoharu Takahashi

A method for assaying a compound of the formula ##STR1## wherein R.sub.1 is hydroxyl or amino, or hydrogen if at least one of R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 is hydroxyl or amino, and R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are hydrogen, halogen, lower alkyl, lower alkoxy, amino, substituted amino, hydroxy, carboxyl or sulfo, or R.sub.5 and R.sub.6 together form a ring, comprises establishing a reaction system containing the compound to be assayed and a coupler and an enzyme capable of consuming oxygen and generating a pigment in the presence of the compound and the coupler. A detectable change in the reaction system is measured, to assay the compound in question. The measurement can comprise the measurement of consumed oxygen, as by an oxygen electrode. Or the measurement can comprise the measurement of the generated pigment, as by a colorimetric assay at a specific absorption wavelength thereof.

Enzymatic assay method

A method for assay of enzyme activity which comprises treating an amide compound of the formula ##STR1## with peptidase; treating thus-liberated amine of the formula ##STR2## with an oxidase which consume oxygen and forms pigment by oxidative condensation of said amine with a coupler of the formula ##STR3## and quantitatively measuring the detectable changes. Also disclosed is an assay method which comprises treating an amide compound of the formula ##STR4## or a salt thereof, with peptidase to liberate an aniline derivative of the formula ##STR5## oxidizing said aniline derivative; and quantitatively measuring detectable change.

Assaying peptidase enzyme activity

A compound of the formula ##STR1## wherein R is L-leucyl or .gamma.-L-glutamyl and X and Y are halogen and are the same or different, or a salt thereof. These compounds are useful as synthetic substrates for assaying peptidase activity.

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Shizuoka, Japan

Tsutomu Hirata