Developmental changes in the isoenzymes controlling glycolysis in the acridine grasshopper,Caledia captiva

Summary In this paper is reported an example of extensive developmental changes in the isoenzymes controlling a biochemical pathway: more than half of the glycolytic enzymes of the grasshopper,Caledia captiva differ in electrophoretic phenotype between embryonic and adult stages. A similar pattern of changes is found in each of the taxa ofC. captiva, which is actually a species complex. The present example of developmental variation differs from that described for glycolytic enzymes in vertebrates in two main points. Firstly, the changes between the phenotypes of the embryos and adults are co-incident in time, occurring near hatching. Secondly, in contrast to vertebrates where embryospecific isoenzymes are rare, there exist inC. captiva isoenzymes of trehalase, glucosephosphate isomerase, aldolase, pyruvate kinase, lactate dehydrogenase and 6-phosphogluconate dehydrogenase which are found in the embryo but not in the adult. Some of the variable enzymes also exhibit tissue specificity in the adult. The existence of the changes, whatever their basis, shows that the theory that the expression of housekeeping genes is developmentally invariant is not generally correct.