METHOD FOR DETERMINING LEUCINE AMINOPEPTIDASE ACTIVITY Russian patent published in 2001 - IPC

FIELD: medicine. SUBSTANCE: method involves incubating material under test with buffer solution of L-leucyl-β- naphthyl amide substrate at 37 C. Enzymatic reaction is stopped by adding hydrochloric acid to the mixture. β-naphthyl amine produced as a result of enzymatic reaction is dinitrogenized by means of sodium nitrite solution which excess quantity is destroyed by adding corresponding substance to the reaction mixture. Dinitrogenized β-naphthylamine is combined with N-(1- naphthyl)-ethylene diamine dihydrochloride with blue color substance produced. Optical density of colored solution is measured. To destroy excess quantity of sodium nitrite, urease is applied. Dinitrogenization of β-naphthyl amine and destruction of excessive quantities of sodium nitrite is carried out concurrently with urease solution in hydrochloric acid added. EFFECT: reduced number of working solutions and procedures; accelerated procedure. 2 tbl