Study of the enzyme assay of dimethylarginine dimethylaminohydrolase in rabbit kidney
- VernacularTitle:兔肾脏DDAH活性测定方法的研究
- Author:
Jian QIN
;
Yunzhen CHEN
;
Zhiguang TU
;
- Publication Type:Journal Article
- Keywords:
rabbits;
kidney;
dimethylarginine dimethylaminohydrolase;
asymmetric dimethylarginine;
methods
- From:
Chinese Pharmacological Bulletin
1987;0(03):-
- CountryChina
- Language:Chinese
-
Abstract:
AIM To establish the method for the enzyme assay of dimethylarginine dimethylaminohydrolase (DDAH) in rabbit kidney and to determine the optimal condition for the assaying. METHODS Five healthy Japanese rabbits weighing 3 0 to 3 5 Kg were killed by air embolism,kidneys were harvested and then were homogenized. Asymmetric dimethylarginine (ADMA) was used as the substrate for DDAH. UV 265 spectrophotometer was applied to determine the amount of the enzymatic product L Citrulline( L Cit).The amount of L Cit produced under different conditions was compared and the optimal condition was screened. The kinetic parameters of ADMA degraded by DDAH were calculated. RESULTS The kinetic parameters of ADMA degraded by DDAH were as follows: K m=(0 28?0 10) mmol?L -1 , V m=(1 36?0 42) mmol?L -1 ?g -1 ?min -1 . The optimal conditions for the enzyme assay of DDAH in rabbit kidney determined in this study follow: The concentration of the enzyme protein was 12 g?L -1 ,the optimal pH of the buffer was 7 4,the final concentration of ADMA was 2 mmol?L -1 ,and the reaction time was 30 min. CONCLUSION The method offered here is easily done. The concentration of the substrate determined in this study was based on the value of Km,thus it was beneficial to the accurate assay of DDAH.
