Preparation and cross‐reactivity of anti‐avian glutamine synthetase antibody

Abstract

Rabbit antibody to chicken liver mitochondrial glutamine synthetase was purified by immunoaffinity chromatography for analysis of the immunological relatedness of vertebrate glutamine synthetases. The antibody cross‐reacted with enzymes from representitives of all five vertebrate classes, indicating a high degree of evolutionary conservatism in the structure of the enzymes. A unique aspect of the immunological similarity of these enzymes is that it exists between cytosolic and mitochondrial enzymes which are, in general, immunologically distinct. The antibody did not cross‐react with two insect glutamine synthetases. Compositional difference indices, calculated from the amino acid compositions of glutamine synthetases from several species, gave a mean estimate of over 80% sequence homology for the vertebrate enzymes. The avian mitochondrial enzyme gave a mean 78% homology with the mammalian cytosolic enzyme.