IMMUNOENZYMOLOGY OF ACETYLCHOLINESTERASE .I. SUBSTRATE SPECIFICITY AND HEAT STABILITY OF ACETYLCHOLINESTERASE AND OF ACETYLCHOLINESTERASE-ANTIBODY COMPLEX

Antibodies to bovine erthrocyte acetylcholinesterase were obtained from rabbits following immunization with the enzyme. The combination of the enzyme with antibodies did not affect its enzymatic activity as measured by Km values and substrate specificity. However, whereas the enzyme was found to lose activity upon heating at 60°C for a period as short as five min, the enzyme in complex with antibody exhibited a remarkable stability at this temperature for the periods tested (up to 90 min). The immune complex, both in the form of a precipitate or in the form of a soluble enzyme-antibody complex, was stable to heat. This phenomenon was demonstrated to be specific for the system of acetylcholinesterase-anti-acetylcholinesterase; no stabilization was effected by the presence of either unrelated globulins or unrelated immune complex. © 1969.