We propose a novel enzymatic method for assay of uric
acid at 340 nm, which eliminates several disadvantages
of ooth the colorimetric and enzymatic methods now in
common use. Here, uric acid is catalytically oxidized to
allantoin and hydrogen peroxide. The peroxide is reacted
with ethanol in the presence of catalase to form acetaldehyde
and water, and the acetaldehyde is reduced by
NADH in the presence of alcohol dehydrogenase to ethanol.
The decrease in absorbance at 340 nm caused by
oxidation of NADH is directly proportional to the concentration
of uric acid in the sample. Measurement of the
change in absorbance between 20 and 200 s eliminates
the need for a serum blank measurement. Absorbance and
concentration are linearly related to 120 mg of uric acid
per liter. The new method was compared with the uricase
method in which decomposition of uric acid at 293 nm is
directly measured. The results for the 47 patients’ sera so
examined can be expressed by the linear