Disease relevance of IVD

• Substrate specificity tests with AtIVD expressed in Escherichia coli indicate a strong preference toward isovaleryl-CoA but surprisingly also show considerable activity with isobutyryl-CoA [1].

High impact information on IVD

• Isovaleryl-CoA dehydrogenase (IVD, EC ) catalyzes the third step in the catabolism of leucine in mammals [2].
• Substrate specificity of the plant enzyme is similar to the human IVD, and it cross-reacts to anti-human IVD antibodies [2].
• In this report we describe the identification and characterization of an IVD from pea, purification of the enzyme using a novel and rapid auxin affinity chromatography matrix, and cloning of the corresponding gene [2].
• Nothing is known about IVD activity in plants, although cDNA clones from Arabidopsis thaliana and partial sequences from Gossypium hirsutum and Oryza sativa have been identified as putative IVDs based on sequence homology and immuno cross-reactivity [2].
• The genomic structure of the plant IVD gene consists of 13 exons and 12 introns, spanning approximately 4 kilobases, and the predicted RNA splicing sites exhibit the extended consensus sequence described for other plant genes [2].

Anatomical context of IVD

• Expression of AtIVD:smGFP4 fusion proteins in tobacco (Nicotiana tabacum) protoplasts and biochemical studies now demonstrate the in vivo import of the plant isovaleryl-CoA dehydrogenase (IVD) into mitochondria and the enzyme in the matrix of these organelles [1].
• Subcellular fractionation identifies the putative IVD enzyme in the mitochondrion [3].

Associations of IVD with chemical compounds

• Such a dual activity has not been observed with the animal IVD and may suggest a novel connection of the Leu and valine catabolism in plants [1].
• We have now identified a candidate protein and corresponding cDNA for an enzyme of the leucine catabolic pathway, the isovaleryl-CoA-dehydrogenase (IVD) [3].
• We recently identified a cDNA encoding a putative isovaleryl-coenzyme A (CoA) dehydrogenase in Arabidopsis (AtIVD) [1].
• Northern-blot hybridization and studies in transgenic Arabidopsis plants expressing Ativd promoter:gus constructs reveal strong expression of this gene in seedlings and young plants grown in the absence of sucrose, whereas promoter activity in almost all tissues is strongly inhibited by exogeneously added sucrose [1].

Analytical, diagnostic and therapeutic context of IVD

• Two-dimensional separation of mitochondrial proteins by blue native and SDS-PAGE and size determination of the native and overexpressed proteins suggest homodimers to be the dominant form of the plant IVD [1].
• Expression of the putative IVD gene in pea seedlings is documented by western blot analyses with an antibody against the mammalian IVD [3].

References