The activation of enzyme was carried out by the periodate treatment. Enzyme immunoassay using antigens conjugated with activated different enzymes including Peroxidase (Horse radish), Alkaline phosphatase (Calf intestine) and Glucose oxidase (Aspergillus niger) was established for routine method. In this system, the antigen determination was carried out by the titration of enzmye activity of supernatant. The liquor or high diluted serum that the neglisible for the endogeneous enzyme activities were easily estimated by this system.
However in this system to titrate the small amount of antigen, for example Alpha-fetoprotein, endogeneous enzyme influenced the enzyme actitity of supernatant, especially Alkaline phosphatase and Peroxidase. To remove Peroxidase activity from serum was accomplished by addition of small amount of perioxid to serum followed by addition of glutaraldehyde fixed sheep red cell. To remove Alkaline phosphatase except heatstable Alkaline phosphatase, for example Reagan phosphatase, was accomplished by heating.
