Molecular cloning, partial genomic structure and functional characterization of succinic semialdehyde dehydrogenase genes from the parasitic insects Lucilia cuprina and Ctenocephalides felis.

The enzyme succinic semialdehyde dehydrogenase (SSADH; EC1.2.1.24) is a component of the gamma-aminobutyric acid degradation pathway in mammals and is essential for development and function of the nervous system. Here we report the identification, cDNA cloning and functional expression of SSADH from the parasitic insects Lucilia cuprina and Ctenocephalides felis. The recombinant proteins possess potent NAD+-dependent SSADH activity, while their catalytic efficiency for other aldehyde substrates is lower. A genomic copy of the L. cuprina SSADH gene contains two introns, while a genomic gene version of C. felis is devoid of introns. In contrast to the single copy SSADH genes in Drosophila melanogaster and mammals, in L. cuprina and C. felis, multiple SSADH gene copies are present in the genome.