The saccharopine dehydrogenase enzyme can be classified under ec 1. Expression of 16 proteins was downregulated in fgv1infected f. Nad oxidoreductase lysine forming showed a strict coenzyme. Three structures of saccharopine dehydrogenase llysineforming sdh have been determined in the presence of sulfate, adenosine monophosphate amp, and oxalylglycine oxgly. Sep 30, 2004 we isolated the gene encoding lysineketoglutarate reductase lkr, ec 1. Sccpdh saccharopine dehydrogenase putative homo sapiens. Saccharopine dehydrogenase an overview sciencedirect.
Dec 20, 2002 lysineketoglutarate reductase saccharopine dehydrogenase lkrsdh is a bifunctional enzyme catalyzing the first two steps of lysine catabolism in animals and plants. Purification and characterization of the bifunctional enzyme. Then, aasa is converted to aminoadipic acid aaa by aaminoadipicdsemialdehyde dehydrogenase aasadh. The genomic dna of fvsdh is 1257 bp, comprising three introns and four exons. A number of nad analogues, including nadp, 3acetylpyridine adenine dinucleotide 3apad, 3pyridinealdehyde adenine dinucleotide 3paad, and. Simultaneous detection of lysine metabolites by a single. Lysineoxoglutarate reductase and saccharopine dehydrogenase are enzymic activities that catalyse the first two steps of lysine degradation through the saccharopine pathway in upper eukaryotes. Crystal structure of saccharopine reductase from magnaporthe. It has an important function in lysine metabolism and. Crystal structures of ligandbound saccharopine dehydrogenase. In molecular biology, the protein domain saccharopine dehydrogenase sdh, also named saccharopine reductase, is an enzyme involved in the metabolism of the amino acid lysine, via an intermediate substance called saccharopine. The next step is catalyzed by saccharopine dehydrogenase sdh, which hydrolyses saccharopine into glutamic acid glu and.
Characterization of the two saccharopine dehydrogenase. Aasa is then converted into aminoadipic acid aaa by aminoadipic semialdehyde dehydrogenase aasadh. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists. Saccharopine dehydrogenase catalyzes the naddependent oxidative deamination of saccharopine to give llysine and.
Saccharopine dehydrogenase an overview sciencedirect topics. The saccharopine pathway in seed development and stress. Lysineketoglutarate reductase and saccharopine dehydrogenase. The lkr and sdh enzymes, which play pivotal role in lys catabolism, are linked on a single bifunctional lkrsdh polypeptide, encoded by a single lkr sdh. Sccpdh saccharopine dehydrogenaselike oxidoreductase. Help pages, faqs, uniprotkb manual, documents, news archive and biocuration projects. A corresponding cdna was isolated from total arabidopsis rna. Lys ketoglutarate reductase lkr first combines lys and. Detection and quantification of lysine degradation metabolites in plasma is necessary for the diagnosis and followup of diseases such as pyridoxinedependent epilepsy.
Then, aasa is converted to aminoadipic acid aaa by aminoadipicsemialdehyde dehydrogenase aasadh. The lysine degradation pathway is also clinically relevant, as several defects in this pathway can cause neurometabolic disorders. Nad oxidoreductase lysineforming is inhibited by high concentrations of alphaketoglutarate and lysine, but not by nadh. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. T assay for lysineketoglutarate reductase by reversedphase highperformance liquid chromatography. We isolated the gene encoding lysineketoglutarate reductase lkr, ec 1. As a member of the wwpdb, the rcsb pdb curates and annotates pdb data according to agreed upon standards. In the direction of reductive condensation of alphaketoglutarate and lysine, saccharopine dehydrogenase n6glutar2ylllysine. The activity of the arabidopsis bifunctional lysine.
Finally, the enzyme saccharopine dehydrogenase sd catalyzes the transformation of saccharopine into llysine by. Regulation of reductase and saccharopine dehydrogenase in. View all proteins of this organism that are known to be involved in the subpathway that synthesizes llysine from lalphaaminoadipate fungal route, the. In animals and plants, the activities of lkr and sdh belong to distinct domains of a bifunc. Pipette in milliliters the following reagents into suitable cuvettes. Our results suggest that lysine catabolism is subject to complex developmental and physiological regulation, which may operate at gene expression as well as posttranslational levels. Saccharopine is an intermediate in lysine metabolism. In the sulfatebound structure, a sulfate ion binds in a cleft between the two domains of sdh, occupies one of the substrate carboxylate binding sites, and results in partial closure of the active site of the enzyme. This paper describes the isolation and characterization of a cdna clone encoding a bifunctional enzyme bearing domains corresponding to these two enzymic activities. Purification and characterization of the bifunctional aminoadipic semialdehyde synthase with lysineketoglutarate reductase and saccharopine dehydrogenase activities. Amino adipic acid is further into acetylcoenzyme a and several additional molecules of glu fig. The other function, called saccharopine dehydrogenase, breaks down saccharopine to a molecule called alphaaminoadipate semialdehyde. Thesetwoenzymes presumably act sequentially in vivo.
Pdf purification and characterization of bifunctional. Arabidopsis plants possess a composite atlkrsdhlocus encoding two different polypeptides involved in lysine catabolism. Source sequences af151807, aw515488, bg258610, bm786495 consensus cds ccds31084. Kg, and lysine analogues has been undertaken in an attempt to define the substrate specificity of saccharopine dehydrogenase and to identify functional groups on all substrates and dinucleotides important for substrate binding. Aass acts as a bifunctional enzyme containing the lysine. Nutritionalrich and stresstolerant crops by saccharopine. In an attempt to determine the contribution to binding and rate enhancement of each of the residues in the active site. Determinants of substrate specificity for saccharopine. There are a number of conserved hydrophilic, ionizable residues in the active site, all of which must be important to the overall reaction.
The reactions involved with saccharopine dehydrogenases have very strict substrate. To elucidate the biochemical signification of the linkage between the two enzymes of lkrsdh, namely lysine ketoglutarate and saccharopine dehydrogenase, we employed various truncated and mutatedarabidopsis lkrsdh polypeptides. Elevated levels of saecharopine, lysine, and citrulline in urine and plasma were observed in a patient suffering from saccharopinuria. These enzymes are involved in the catabolism of lysine, and in plants and mammals saccharopine reductase functions as a saccharopine dehydrogenase. Succinate dehydrogenase is one of the enzymes of the krebs cycle a in the space from biochem 301 at duke university. Marymar goncalvesbutruille, patricia szajner, emi torigoi, adilson leite. Allysine reacts with a glutamic acid through a nadph dependent saccharopine dehydrogenase resulting in the release of water, nadp and saccharopine. A tdna insertion knockout of the bifunctional lysine. Simultaneous detection of lysine metabolites by a single lc.
Sccpdh saccharopine dehydrogenaselike oxidoreductase mus. Therefore any saccharopine formed from lysine would rapidly be converted into a. Lkrsdh plays important roles throughout the tick life cycle. The prokaryotic pathway of l lysine biosynthesis via l 2aminoadipate was found in a hyperthermophilic gramnegative eubacterium thermus thermophilus, and n 2acetyl l lysine is the intermediate being converted to l lysine. The principal metabolites involved in the disease are related to the first steps of lysine oxidation, either through the saccharopine or the pipecolate pathways. See pdf for structure the enzyme catalyzing the terminal reaction, saccharopine dehydrogenase. In silicibacter, the contiguous lkr and sdh genes are inter spersed, in another frame, by a polypeptide of.
Pdf saccharopine, an intermediate of the aminoadipic acid. Patient fibroblasts showed undetectable activities of both lysine ketoglutarate reductase and saccharopine dehydrogenase. The lkrsdh amino acid sequences used were downloaded from. Fujioka, m takata, y role of arginine residue in saccharopine dehydrogenase llysine forming from bakers yeast. Reexamination of the urine of previously studied cases of this double enzyme deficiency dancis et al. The rcsb pdb also provides a variety of tools and resources. The enzyme catalyzing the terminal reaction, saccharopine dehydrogenase.
Succinate dehydrogenase is one of the enzymes of the krebs. Saccharopine reacts with a water molecule and a nad dependent saccharopine dehydrogenase resulting in the release of oxoglutaric acid and llysine. Saccharopine is then converted by saccharopine dehydrogenase sdh to glu and. Lorsdh has been isolated from plant tissues which allowed the characterisation of some physical and biochemical properties, kinetics and modulation of lor activity by calcium, ionic strength, and. Lysine degradation through the saccharopine pathway in. Lysineketoglutarate reductase and saccharopine dehydrogenase from arabidopsis thaliana.
The pathway of lysine degradation in mammalian liver 1 saccharopine from bchs 3305 at university of houston. The downregulation of lkrsdh in seeds results in the overaccumulation of free lysine to levels that meet human nutritional requirements. Download pdf orphanet journal of rare diseases biomed central. Lysineketoglutarate reductasesaccharopine dehydrogenase lkrsdh. The gene fvsdh encoding saccharopine dehydrogenase was identified and cloned from the whole genome of flammulina velutipes. Saccharopine, a lysine degradation intermediate, is a. It has a role as a human metabolite, a saccharomyces cerevisiae metabolite and a mouse metabolite. Saccharopine, an intermediate of the aminoadipic acid pathway of. However, dna gel blot hybridization using either the lysineketoglutarate reductase or the saccharopine dehydrogenase cdna sequence as a probe suggested that the two mrna populations apparently are encoded by the same gene.
Pdf saccharopine, an intermediate of the aminoadipic. Lysine degradation through the saccharopine pathway in bacteria. Overexpression of the saccharopine dehydrogenase gene. Feature key positions description actions graphical view length. Lysine is catabolized via the saccharopine pathway in plants and mammals. Genomewide analysis of lysine catabolism in bacteria reveals new. The pathway of lysine degradation in mammalian liver 1. Regulation of lysine catabolism through lysineketoglutarate reductase and saccharopine dehydrogenase in arabidopsis. L saccharopine is the n61,3dicarboxypropan1yl derivative of llysine. Both in mammals and plants, excess lysine lys is catabolized via saccharopine into.
Currently, there are three different analytical methods used to. Saccharopine dehydrogenase journal of biological chemistry. Saccharopine dehydrogenase like oxidoreductase add blast. Glutamates 78 and 122 in the active site of saccharopine. Saccharopine dehydrogenase enzyme solution immediately before use, prepare a solution containing 0. Saccharopine dehydrogenase can also function as a saccharopine reductase. Here, we show that bacteria possess the genes encoding lysineketoglutarate reductase lkr and saccharopine dehydrogenase sdh.
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