Correlation between the Values of Serum GOT and GPT Activities Obtained by the Diazotized Sulfanilic Acid Method and the Improved Reitman-Frankel Method
1972 Volume 1 Issue 2 Pages 215-219
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1972 Volume 1 Issue 2 Pages 215-219
The correlation between the values of serum GOT and GPT activities obtained by the following two assay methods was studied. One is the previously established colorimetric method based on measuring the amount of 2-oxoglutaric acid consumed in the enzyme reaction utilizing diazotized sulfanilic acid as the selective color developing agent for the acid (DS method), and the other is the improved Reitman-Frankel method which uses 2mM 2, 4-dinitrophenylhydrazine solution and 0.2N sodium hydroxide solution containing 0.1M potassium sodium tartarate in color development (improved R-F method).
The values of enzyme activities obtained by the normal procedure (with serum blank) in the improved R-F method were compared with those obtained by the procedure without serum blank, in order to know which procedure should be compared with the DS method. The results (Fig. 1) indicated that the coloration due to serum might often contribute greatly to give an erroneously higher value. Therefore, the normal procedure should be employed even in routine assay.
The correlation between the values determined by the normal procedure of the improved R-F method and the DS method (Fig. 2) was shown by the quadratic regression equations described in the text. In the equations, Yo and Yp are the values of GOT and GPT activities in the improved R-F method (Karmen unit), respectively, and Xo and Xp are those of GOT and GPT activities in the Ds method,(the unit is expressed as the number ofit moles of 2-oxoglutaric acid consumed by 1000ml of serum permin at 37°), respectively.
The color reacticn utilized in the DS method is fairly selective for 2-oxoglutaric acid, and tha method seems to be more favorable than the Reitman-Frankel method as a colorimetric method for measuring the enzyme activities inserum
