Site specific antibodies directed to the ATP binding region of some kinases

Polyclonal antibodies raised in rabbits to ATP-requiring enzymes such as 3-phosphoglycerate kinase show cross-reactivity against other unrelated kinases. Our results show that rabbit polyclonal antiserum possesses antibodies that recognize an antigenic site at the ATP binding region of kinases. A classical immunotitration curve was obtained when hexokinase was titrated against anti-myokinase IgG. The immunoinhibitions was reversed in the presence of small concentration of ATP. This cross-reactivity between site specific antibody and unrelated kinase demonstrates the existence of an antigenic site around the ATP binding region. Our proposal of the existence of a common antigenic determinant in the ATP binding region is in agreement with the finding of a common structural domain that binds ATP.