On the immunological inter-relationships of the vertebrate esterases

Abstract

1. 1. In order to assess the immunological inter-relationships of the vertebrate esterases, antisera were produced against several purified enzymes from the different esterolytic classifications, namely sheep liver carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1.), horse serum cholinesterase (acylcholine acyl-hydrolase, EC 3.1.1.8), ox testis acetylesterase (acetic-ester hydrolase, EC 3.1.1.6) and ox serum arylesterase (acyl-ester hydrolase, EC 3.1.1.2). 2. 2. These antisera were tested for their interactions at the level of enzyme heterogeneity, by gel electrophoresis of a representative range of tissues before and after incubation with the sera, followed by observation of the alteration in the patterns of esterase heteromorphs consequent upon this treatment. 3. 3. From these results, it appears that a close immunological relationship exists between the multiple forms of each individual esterase type within a single species. In the case of the acetylesterases, this immunological relationship extends between the species as well. A close relationship was also observed between chicken liver carboxylesterase and horse serum cholinesterase, and to a lesser degree between these two latter enzymes and sheep liver carboxylesterase. 4. 4. In addition to the electrophoretic studies, complement fixation inhibition assays were carried out between each of the antisera and all the purified antigens. Also, micro-complement fixation assays between the antisera to the chicken liver carboxylesterase and horse serum cholinesterase were effected with all the antigens. These immunological tests with pure enzymes served to verify that a degree of relationship exists between the hose cholinesterase and the chicken carboxylesterase. 5. 5. The significance of these results has been discussed in relation to the phylogenetic variability of the esterases, the complex structural and genetic inter-relationships of these multiple enzyme forms, and the comparative situation in intensively studied isoenzyme systems.