Abstract
Bivalent metal salts, such as Zn, Mg, Mn, Cd etc. of 6-benzamido-4-methoxy-m-toluidine diazonium chloride are more stable than its free diazonium chloride. These salts react easily with oxalacetate at room temperature in alkaline medium to form the colour substance having the maximum optical density at 520 mμ. Using these zinc salts as the colour developing reagents for oxalacetate, we established the routine assay method of glutamic-oxalacetic transaminase, and malic dehydrogenase activities in serum. Upon measuring GOT activity in serum of patients by three different methods (diazonium salt method, Karmen method and Reitman・Frankel method), we came to a conclusion that this new diazonium method was very advantageous to Reitman・Frankel method in accuracy and simplicity for clinicians.
